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Feature Papers in Materials Chemistry

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Materials Chemistry".

Deadline for manuscript submissions: closed (31 August 2023) | Viewed by 88252

Special Issue Editors

Dr. Giuseppe Cirillo

E-Mail Website
Guest Editor
Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende, Italy
Interests: nanomaterials; biomaterials; carbon nanostructures; composite and hybrid materials; biomedical applications of functional materials; therapeutic devices; surface chemistry
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Guankui Long

E-Mail Website
Guest Editor
School of Materials Science and Engineering, Nankai University, Tianjin 300350, China
Interests: chiral perovskites; chiroptics; chirospintronics; organic solar cells; theoretical calculations
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Tomasz Sadowski

E-Mail Website
Guest Editor
Department of Solid Mechanics, Faculty of Civil Engineering and Architecture, Lublin University of Technology, Nadbystrzycka 40 Str., 20-618 Lublin, Poland
Interests: fluid mechanics; finite element analysis; computational fluid dynamics CFD; simulation engineering; thermodynamics; computational fluid mechanics; numerical simulation; turbulence numerical modeling; aerodynamics design engineering; mechanical properties engineering; applied and computational mathematics engineering; optimization engineering drawing; fluid structure interaction; piping; computational analysis; multidisciplinary design; optimization FSI; aeroelasticity patient simulation; FLUENTCFD coding modeling and simulation; thermal engineering; experimental fluid mechanics; turbulence modeling; numerical analysis; convection heat transfer; solid mechanics; civil engineering; finite element methods; ABAQUS mechanical engineering; aerospace; environmental impact assessment; fracture; material characterization; composites elasticity; fracture mechanics; ceramics materials; composite material alginate
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The Special Issue aims to highlight the recent developments across all fields of materials chemistry. We are collecting invited papers on materials in biomedical, energy, environmental, and other applications by leading scientists across the world. Research articles and review papers on the synthesis, properties, and characterization of organic, inorganic, and hybrid materials are welcome. 

Dr. Giuseppe Cirillo
Prof. Dr. Guankui Long
Prof. Dr. Tomasz Sadowski
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • materials chemistry
  • organic materials
  • inorganic materials
  • hybrid materials
  • biomedical materials
  • energy materials
  • environmental materials
  • functional materials

Published Papers (48 papers)

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19 pages, 4571 KiB  
Article
Investigating the Influence of Diffusion on the Cohesive Zone Model of the SiC/Al Composite Interface
by Masoud Tahani, Eligiusz Postek and Tomasz Sadowski
Molecules 2023, 28(19), 6757; https://doi.org/10.3390/molecules28196757 - 22 Sep 2023
Cited by 2 | Viewed by 736
Abstract
Modeling metal matrix composites in finite element software requires incorporating a cohesive zone model (CZM) to represent the interface between the constituent materials. The CZM determines the behavior of traction–separation (T–S) in this region. Specifically, when a diffusion zone is formed due to [...] Read more.
Modeling metal matrix composites in finite element software requires incorporating a cohesive zone model (CZM) to represent the interface between the constituent materials. The CZM determines the behavior of traction–separation (T–S) in this region. Specifically, when a diffusion zone is formed due to heat treatment, it becomes challenging to determine experimentally the equivalent mechanical properties of the interface. Additionally, understanding the influence of heat treatment and the creation of a diffusion zone on the T–S law is crucial. In this study, the molecular dynamics approach was employed to investigate the effect of the diffusion region formation, resulting from heat treatment, on the T–S law at the interface of a SiC/Al composite in tensile, shear, and mixed-mode loadings. It was found that the formation of a diffusion layer led to an increase in tensile and shear strengths and work of separation compared with the interfaces without heat treatment. However, the elastic and shear moduli were not significantly affected by the creation of the diffusion layer. Moreover, the numerical findings indicated that the shear strength in the diffusion region was higher when compared with the shear strength of the {111} slip plane within the fcc aluminum component of the composite material. Therefore, in the diffusion region, crack propagation did not occur in the pure shear loading case; however, shear sliding was observed at the aluminum atomic layers. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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12 pages, 2229 KiB  
Article
Degradation Behavior of Poly(Lactide-Co-Glycolide) Monolayers Investigated by Langmuir Technique: Accelerating Effect
by Gayeon Kim, Vishal Gavande, Vasi Shaikh and Won-Ki Lee
Molecules 2023, 28(12), 4810; https://doi.org/10.3390/molecules28124810 - 16 Jun 2023
Cited by 2 | Viewed by 1338
Abstract
Among biodegradable polymers, polylactides (PLAs) have attracted considerable interest because the monomer can be produced from renewable resources. Since their initial degradability strongly affects commercial application fields, it is necessary to manage the degradation properties of PLAs to make them more commercially attractive. [...] Read more.
Among biodegradable polymers, polylactides (PLAs) have attracted considerable interest because the monomer can be produced from renewable resources. Since their initial degradability strongly affects commercial application fields, it is necessary to manage the degradation properties of PLAs to make them more commercially attractive. To control their degradability, poly(lactide-co-glycolide) (PLGA) copolymers of glycolide and isomer lactides (LAs) were synthesized, and their enzymatic and alkaline degradation rates of PLGA monolayers as functions of glycolide acid (GA) composition were systematically investigated by the Langmuir technique. The results showed that the alkaline and enzymatic degradations of PLGA monolayers were faster than those of l-polylactide (l-PLA), even though proteinase K is selectively effective in the l-lactide (l-LA) unit. Alkaline hydrolysis was strongly affected by their hydrophilicity, while the surface pressure of monolayers for enzymatic degradations was a major factor. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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12 pages, 3284 KiB  
Article
Novel Red-Emitting Eu3+-Doped Y2(WxMo1−xO4)3 Phosphor with High Conversion Efficiency for Lighting and Display Applications
by Fan Chen, Muhammad Nadeem Akram and Xuyuan Chen
Molecules 2023, 28(12), 4624; https://doi.org/10.3390/molecules28124624 - 07 Jun 2023
Cited by 2 | Viewed by 4697
Abstract
In this study, a series of trivalent europium-doped tungstate and molybdate samples were synthesized using an improved sol-gel and high-temperature solid-state reaction method. The samples had different W/Mo ratios and were calcined at various temperatures ranging from 800 to 1000 °C. The effects [...] Read more.
In this study, a series of trivalent europium-doped tungstate and molybdate samples were synthesized using an improved sol-gel and high-temperature solid-state reaction method. The samples had different W/Mo ratios and were calcined at various temperatures ranging from 800 to 1000 °C. The effects of these variables on the crystal structure and photoluminescence characteristics of the samples were investigated. It was found that a doping concentration of 50% for europium yielded the best quantum efficiency based on previous research. The crystal structures were found to be dependent on the W/Mo ratio and calcination temperature. Samples with x ≤ 0.5 had a monoclinic lattice structure that did not change with calcination temperature. Samples with x > 0.75 had a tetragonal structure that remained unchanged with calcination temperature. However, samples with x = 0.75 had their crystal structure solely dependent on the calcination temperature. At 800–900 °C, the crystal structure was tetragonal, while at 1000 °C, it was monoclinic. Photoluminescence behavior was found to correlate with crystal structure and grain size. The tetragonal structure had significantly higher internal quantum efficiency than the monoclinic structure, and smaller grain size had higher internal quantum efficiency than larger grain size. External quantum efficiency initially increased with increasing grain size and then decreased. The highest external quantum efficiency was observed at a calcination temperature of 900 °C. These findings provide insight into the factors affecting the crystal structure and photoluminescence behavior in trivalent europium-doped tungstate and molybdate systems. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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23 pages, 6446 KiB  
Article
Building Fucoidan/Agarose-Based Hydrogels as a Platform for the Development of Therapeutic Approaches against Diabetes
by Lara L. Reys, Simone S. Silva, Diana Soares da Costa, Luísa C. Rodrigues, Rui L. Reis and Tiago H. Silva
Molecules 2023, 28(11), 4523; https://doi.org/10.3390/molecules28114523 - 02 Jun 2023
Cited by 1 | Viewed by 1516
Abstract
Current management for diabetes has stimulated the development of versatile 3D-based hydrogels as in vitro platforms for insulin release and as support for the encapsulation of pancreatic cells and islets of Langerhans. This work aimed to create agarose/fucoidan hydrogels to encapsulate pancreatic cells [...] Read more.
Current management for diabetes has stimulated the development of versatile 3D-based hydrogels as in vitro platforms for insulin release and as support for the encapsulation of pancreatic cells and islets of Langerhans. This work aimed to create agarose/fucoidan hydrogels to encapsulate pancreatic cells as a potential biomaterial for diabetes therapeutics. The hydrogels were produced by combining fucoidan (Fu) and agarose (Aga), marine polysaccharides derived from the cell wall of brown and red seaweeds, respectively, and a thermal gelation process. The agarose/fucoidan (AgaFu) blended hydrogels were obtained by dissolving Aga in 3 or 5 wt % Fu aqueous solutions to obtain different proportions (4:10; 5:10, and 7:10 wt). The rheological tests on hydrogels revealed a non-Newtonian and viscoelastic behavior, while the characterization confirmed the presence of the two polymers in the structure of the hydrogels. In addition, the mechanical behavior showed that increasing Aga concentrations resulted in hydrogels with higher Young’s modulus. Further, the ability of the developed materials to sustain the viability of human pancreatic cells was assessed by encapsulation of the 1.1B4HP cell line for up to 7 days. The biological assessment of the hydrogels revealed that cultured pancreatic beta cells tended to self-organize and form pseudo-islets during the period studied. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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23 pages, 5031 KiB  
Article
Synthesis of Ketjenblack Decorated Pillared Ni(Fe) Metal-Organic Frameworks as Precursor Electrocatalysts for Enhancing the Oxygen Evolution Reaction
by Thi Hai Yen Beglau, Lars Rademacher, Robert Oestreich and Christoph Janiak
Molecules 2023, 28(11), 4464; https://doi.org/10.3390/molecules28114464 - 31 May 2023
Cited by 4 | Viewed by 1574
Abstract
Metal-organic frameworks (MOFs) have been investigated with regard to the oxygen evolution reaction (OER) due to their structure diversity, high specific surface area, adjustable pore size, and abundant active sites. However, the poor conductivity of most MOFs restricts this application. Herein, through a [...] Read more.
Metal-organic frameworks (MOFs) have been investigated with regard to the oxygen evolution reaction (OER) due to their structure diversity, high specific surface area, adjustable pore size, and abundant active sites. However, the poor conductivity of most MOFs restricts this application. Herein, through a facile one-step solvothermal method, the Ni-based pillared metal-organic framework [Ni2(BDC)2DABCO] (BDC = 1,4-benzenedicarboxylate, DABCO = 1,4-diazabicyclo[2.2.2]octane), its bimetallic nickel-iron form [Ni(Fe)(BDC)2DABCO], and their modified Ketjenblack (mKB) composites were synthesized and tested toward OER in an alkaline medium (KOH 1 mol L−1). A synergistic effect of the bimetallic nickel-iron MOF and the conductive mKB additive enhanced the catalytic activity of the MOF/mKB composites. All MOF/mKB composite samples (7, 14, 22, and 34 wt.% mKB) indicated much higher OER performances than the MOFs and mKB alone. The Ni-MOF/mKB14 composite (14 wt.% of mKB) demonstrated an overpotential of 294 mV at a current density of 10 mA cm−2 and a Tafel slope of 32 mV dec−1, which is comparable with commercial RuO2, commonly used as a benchmark material for OER. The catalytic performance of Ni(Fe)MOF/mKB14 (0.57 wt.% Fe) was further improved to an overpotential of 279 mV at a current density of 10 mA cm−2. The low Tafel slope of 25 mV dec−1 as well as a low reaction resistance due to the electrochemical impedance spectroscopy (EIS) measurement confirmed the excellent OER performance of the Ni(Fe)MOF/mKB14 composite. For practical applications, the Ni(Fe)MOF/mKB14 electrocatalyst was impregnated into commercial nickel foam (NF), where overpotentials of 247 and 291 mV at current densities of 10 and 50 mA cm−2, respectively, were realized. The activity was maintained for 30 h at the applied current density of 50 mA cm−2. More importantly, this work adds to the fundamental understanding of the in situ transformation of Ni(Fe)DMOF into OER-active α/β-Ni(OH)2, β/γ-NiOOH, and FeOOH with residual porosity inherited from the MOF structure, as seen by powder X-ray diffractometry and N2 sorption analysis. Benefitting from the porosity structure of the MOF precursor, the nickel-iron catalysts outperformed the solely Ni-based catalysts due to their synergistic effects and exhibited superior catalytic activity and long-term stability in OER. In addition, by introducing mKB as a conductive carbon additive in the MOF structure, a homogeneous conductive network was constructed to improve the electronic conductivity of the MOF/mKB composites. The electrocatalytic system consisting of earth-abundant Ni and Fe metals only is attractive for the development of efficient, practical, and economical energy conversion materials for efficient OER activity. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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19 pages, 13211 KiB  
Article
Mechanical and Electronic Properties of Al(111)/6H-SiC Interfaces: A DFT Study
by Mostafa Fathalian, Eligiusz Postek and Tomasz Sadowski
Molecules 2023, 28(11), 4345; https://doi.org/10.3390/molecules28114345 - 25 May 2023
Cited by 2 | Viewed by 1419
Abstract
A density functional theory (DFT) calculation is carried out in this work to investigate the effect of vacancies on the behavior of Al(111)/6H SiC composites. Generally, DFT simulations with appropriate interface models can be an acceptable alternative to experimental methods. We developed two [...] Read more.
A density functional theory (DFT) calculation is carried out in this work to investigate the effect of vacancies on the behavior of Al(111)/6H SiC composites. Generally, DFT simulations with appropriate interface models can be an acceptable alternative to experimental methods. We developed two modes for Al/SiC superlattices: C-terminated and Si-terminated interface configurations. C and Si vacancies reduce interfacial adhesion near the interface, while Al vacancies have little effect. Supercells are stretched vertically along the z-direction to obtain tensile strength. Stress–strain diagrams illustrate that the tensile properties of the composite can be improved by the presence of a vacancy, particularly on the SiC side, compared to a composite without a vacancy. Determining the interfacial fracture toughness plays a pivotal role in evaluating the resistance of materials to failure. The fracture toughness of Al/SiC is calculated using the first principal calculations in this paper. Young’s modulus (E) and surface energy (Ɣ) is calculated to obtain the fracture toughness (KIC). Young’s modulus is higher for C-terminated configurations than for Si-terminated configurations. Surface energy plays a dominant role in determining the fracture toughness process. Finally, to better understand the electronic properties of this system, the density of states (DOS) is calculated. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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12 pages, 2899 KiB  
Article
Delivery of Active Peptides by Self-Healing, Biocompatible and Supramolecular Hydrogels
by Seyedeh Rojin Shariati Pour, Sara Oddis, Marianna Barbalinardo, Paolo Ravarino, Massimiliano Cavallini, Jessica Fiori, Demetra Giuri and Claudia Tomasini
Molecules 2023, 28(6), 2528; https://doi.org/10.3390/molecules28062528 - 10 Mar 2023
Cited by 5 | Viewed by 1708
Abstract
Supramolecular and biocompatible hydrogels with a tunable pH ranging from 5.5 to 7.6 lead to a wide variety of formulations useful for many different topical applications compatible with the skin pH. An in vitro viability/cytotoxicity test of the gel components demonstrated that they [...] Read more.
Supramolecular and biocompatible hydrogels with a tunable pH ranging from 5.5 to 7.6 lead to a wide variety of formulations useful for many different topical applications compatible with the skin pH. An in vitro viability/cytotoxicity test of the gel components demonstrated that they are non-toxic, as the cells continue to proliferate after 48 h. An analysis of the mechanical properties demonstrates that the hydrogels have moderate strength and an excellent linear viscoelastic range with the absence of a proper breaking point, confirmed with thixotropy experiments. Two cosmetic active peptides (Trifluoroacetyl tripeptide-2 and Palmitoyl tripeptide-5) were successfully added to the hydrogels and their transdermal permeation was analysed with Franz diffusion cells. The liquid chromatography-mass spectrometry (HPLC-MS) analyses of the withdrawn samples from the receiving solutions showed that Trifluoroacetyl tripeptide-2 permeated in a considerable amount while almost no transdermal permeation of Palmitoyl tripeptide-5 was observed. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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15 pages, 5820 KiB  
Article
Binderless Faujasite Beads with Hierarchical Porosity for Selective CO2 Adsorption for Biogas Upgrading
by Dina G. Boer, Zahra Asgar Pour, Jort Langerak, Benny Bakker and Paolo P. Pescarmona
Molecules 2023, 28(5), 2198; https://doi.org/10.3390/molecules28052198 - 27 Feb 2023
Cited by 3 | Viewed by 1434
Abstract
Biomethane can be isolated from biogas through selective CO2 adsorption. Faujasite-type zeolites are promising adsorbents for CO2 separation due to their high CO2 adsorption capacity. While commonly inert binder materials are used to shape zeolite powders into the desired macroscopic [...] Read more.
Biomethane can be isolated from biogas through selective CO2 adsorption. Faujasite-type zeolites are promising adsorbents for CO2 separation due to their high CO2 adsorption capacity. While commonly inert binder materials are used to shape zeolite powders into the desired macroscopic format for application in an adsorption column, here we report the synthesis of Faujasite beads without the use of a binder and their application as CO2-adsorbents. Three types of binderless Faujasite beads (d = 0.4–0.8 mm) were synthesized using an anion-exchange resin hard template. All the prepared beads consisted mostly of small Faujasite crystals, as demonstrated by characterization with XRD and SEM, which are interconnected through a network of meso- and macropores (10–100 nm), yielding a hierarchically porous structure, as shown by N2 physisorption and SEM. The zeolitic beads showed high CO2 adsorption capacity (up to 4.3 mmol g−1 at 1 bar and 3.7 mmol g−1 at 0.4 bar) and CO2/CH4 selectivity (up to 19 at the partial pressures mimicking biogas, i.e., 0.4 bar CO2 and 0.6 bar CH4). Additionally, the synthesized beads have a stronger interaction with CO2 than the commercial zeolite powder (enthalpy of adsorption −45 kJ mol−1 compared to −37 kJ mol−1). Therefore, they are also suitable for CO2 adsorption from gas streams in which the CO2 concentration is relatively low, such as flue gas. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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16 pages, 6022 KiB  
Article
Click-Functionalization of Silanized Carbon Nanotubes: From Inorganic Heterostructures to Biosensing Nanohybrids
by Gririraj Manoharan, Petra Bösel, Jannis Thien, Michael Holtmannspötter, Laura Meingast, Mercedes Schmidt, Henning Eickmeier, Markus Haase, Janina Maultzsch, Martin Steinhart, Joachim Wollschläger, Matteo Palma and Carola Meyer
Molecules 2023, 28(5), 2161; https://doi.org/10.3390/molecules28052161 - 25 Feb 2023
Viewed by 2433
Abstract
Here we present an approach to functionalize silanized single-walled carbon nanotubes (SWNTs) through copper-free click chemistry for the assembly of inorganic and biological nanohybrids. The nanotube functionalization route involves silanization and strain-promoted azide–alkyne cycloaddition reactions (SPACC). This was characterized by X-ray photoelectron spectroscopy, [...] Read more.
Here we present an approach to functionalize silanized single-walled carbon nanotubes (SWNTs) through copper-free click chemistry for the assembly of inorganic and biological nanohybrids. The nanotube functionalization route involves silanization and strain-promoted azide–alkyne cycloaddition reactions (SPACC). This was characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and Fourier transform infra-red spectroscopy. Silane–azide-functionalized SWNTs were immobilized from solution onto patterned substrates through dielectrophoresis (DEP). We demonstrate the general applicability of our strategy for the functionalization of SWNTs with metal nanoparticles (gold nanoparticles), fluorescent dyes (Alexa Fluor 647) and biomolecules (aptamers). In this regard, dopamine-binding aptamers were conjugated to the functionalized SWNTs to perform real-time detection of dopamine at different concentrations. Additionally, the chemical route is shown to selectively functionalize individual nanotubes grown on the surface of silicon substrates, contributing towards future nano electronic device applications. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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15 pages, 3114 KiB  
Article
Design of TiO2-Surfactin Hybrid Systems with Multifunctional Properties
by Simona Ortelli, Maurizio Vespignani, Ilaria Zanoni, Magda Blosi, Claudia Vineis, Andreana Piancastelli, Giovanni Baldi, Valentina Dami, Stefania Albonetti and Anna Luisa Costa
Molecules 2023, 28(4), 1863; https://doi.org/10.3390/molecules28041863 - 16 Feb 2023
Cited by 1 | Viewed by 1322
Abstract
In recent years, multifunctional inorganic−organic hybrid materials have been widely investigated in order to determine their potential synergetic, antagonist, or independent effects in terms of reactivity. The aim of this study was to design and characterize a new hybrid material by coupling well-known [...] Read more.
In recent years, multifunctional inorganic−organic hybrid materials have been widely investigated in order to determine their potential synergetic, antagonist, or independent effects in terms of reactivity. The aim of this study was to design and characterize a new hybrid material by coupling well-known photocatalytic TiO2 nanoparticles with sodium surfactin (SS), a biosurfactant showing high binding affinity for metal cations as well as the ability to interact with and disrupt microorganisms’ cell membranes. We used both chemical and colloidal synthesis methodologies and investigated how different TiO2:SS weight ratios affected colloidal, physicochemical, and functional properties. We discovered a clear breaking point between TiO2 and SS single-component trends and identified different ranges of applicability by considering different functional properties such as photocatalytic, heavy metal sorption capacity, and antibacterial properties. At low SS contents, the photocatalytic properties of TiO2 are preserved (conversion of organic dye = 99% after 40 min), and the hybrid system can be used in advanced oxidation processes, taking advantage of the additional antimicrobial SS properties. At high SS contents, the TiO2 photoactivity is inhibited, and the hybrid can be usefully exploited as a UV blocker in cosmetics, avoiding undesired oxidative effects (UV adsorption in the range between 300–400 nm). Around the breaking point (TiO2:SS 1:1), the hybrid material preserves the high surface area of TiO2 (specific surface area around 180 m2/g) and demonstrates NOx depletion of up to 100% in 80 min, together with improved adhesion of hybrid antibacterial coating. The last design demonstrated the best results for the concurrent removal of inorganic, organic, and biological pollutants in water/soil remediation applications. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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17 pages, 4375 KiB  
Article
Two-Photon Absorption and Multiphoton Excited Fluorescence of Acetamide-Chalcone Derivatives: The Role of Dimethylamine Group on the Nonlinear Optical and Photophysical Properties
by André Gasparotto Pelosi, Eli Silveira-Alves, Jr., Leandro Henrique Zucolotto Cocca, João Victor Valverde, Guilherme Roberto Oliveira, Daniel Luiz da Silva, Leonardo De Boni, Pablo José Gonçalves and Cleber Renato Mendonca
Molecules 2023, 28(4), 1572; https://doi.org/10.3390/molecules28041572 - 06 Feb 2023
Cited by 2 | Viewed by 1775
Abstract
This work studied the effect of different electron-withdrawing and electron-donating groups on the linear and nonlinear optical properties of acetamide-chalcone derivatives. The results showed that the addition of the dimethylamine group led to a large fluorescence emission (71% of fluorescence quantum yield in [...] Read more.
This work studied the effect of different electron-withdrawing and electron-donating groups on the linear and nonlinear optical properties of acetamide-chalcone derivatives. The results showed that the addition of the dimethylamine group led to a large fluorescence emission (71% of fluorescence quantum yield in DMSO solution) that can be triggered by two and three-photon excitations, which is essential for biological applications. Furthermore, dimethylamine also red-shifts the lower energy state by approximately 90 nm, increasing the two-photon absorption cross-section of the lower energy band by more than 100% compared with the other studied compounds. All compounds presented two-electronic states observed through one and two-photon absorption spectroscopy and confirmed by Quantum Chemistry Calculations (QCCs). QCC results were also used to model the experimental two-photon absorption cross-sectional spectrum by the Sum-Over-States (SOS) approach, revealing a dependence between the coupling of the ground state with the first excited state and the transition dipole moment between these states. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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14 pages, 3831 KiB  
Article
Improved Photoluminescence Performance of Eu3+-Doped Y2(MoO4)3 Red-Emitting Phosphor via Orderly Arrangement of the Crystal Lattice
by Fan Chen, Muhammad Nadeem Akram and Xuyuan Chen
Molecules 2023, 28(3), 1014; https://doi.org/10.3390/molecules28031014 - 19 Jan 2023
Cited by 4 | Viewed by 1340
Abstract
In this study, we developed a technology for broadening the 465 nm and 535 nm excitation peaks of Eu3+:Y2(MoO4)3 via crystal lattice orderly arrangement. This was achieved by powder particle aggregation and diffusion at a high [...] Read more.
In this study, we developed a technology for broadening the 465 nm and 535 nm excitation peaks of Eu3+:Y2(MoO4)3 via crystal lattice orderly arrangement. This was achieved by powder particle aggregation and diffusion at a high temperature to form a ceramic structure. The powdered Eu3+:Y2(MoO4)3 was synthesized using the combination of a sol–gel process and the high-temperature solid-state reaction method, and it then became ceramic via a sintering process. Compared with the Eu3+:Y2(MoO4)3 powder, the full width at half maximum (FWHM) of the excitation peak of the ceramic was broadened by two- to three-fold. In addition, the absorption efficiency of the ceramic was increased from 15% to 70%, while the internal quantum efficiency reduced slightly from 95% to 90%, and the external quantum efficiency was enhanced from 20% to 61%. More interestingly, the Eu3+:Y2(MoO4)3 ceramic material showed little thermal quenching below a temperature of 473 K, making it useful for high-lumen output operating at a high temperature. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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16 pages, 1547 KiB  
Article
Synthesis and Behavior of Hexamethylenetetramine-Based Ionic Liquids as an Active Ingredient in Latent Curing Formulations with Ethylene Glycol for DGEBA
by Dawid Zielinski, Andrea Szpecht, Paulina Hinc and Marcin Smiglak
Molecules 2023, 28(2), 892; https://doi.org/10.3390/molecules28020892 - 16 Jan 2023
Cited by 4 | Viewed by 2742
Abstract
The paper presents the preparation of new ionic liquids based on hexamethylenetetramine with bis(trifluoromethanesulfonyl)imide and dicyanamide anion, which were characterized in detail in terms of their purity (Ion Chromatography) and thermal properties (Differential Scanning Calorimetry), as well as stability. The obtained substances were [...] Read more.
The paper presents the preparation of new ionic liquids based on hexamethylenetetramine with bis(trifluoromethanesulfonyl)imide and dicyanamide anion, which were characterized in detail in terms of their purity (Ion Chromatography) and thermal properties (Differential Scanning Calorimetry), as well as stability. The obtained substances were used to develop curing systems with ethylene glycol, which were successfully tested for their application with bisphenol A diglycidyl ether molecule. In addition, the curing process and its relationship to the structure of the ionic liquid are characterized in detail. The research showed that hexamethylenetetramine-based new ionic liquids can be successfully designed using well-known and simple synthetic methods—the Delepine reaction. Moreover, attention was paid to their stability, related limitations, and the application of hexamethylenetetramine-based ionic liquids in epoxy-curing systems. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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17 pages, 7641 KiB  
Article
Effect of Vacancy Defect Content on the Interdiffusion of Cubic and Hexagonal SiC/Al Interfaces: A Molecular Dynamics Study
by Masoud Tahani, Eligiusz Postek, Leili Motevalizadeh and Tomasz Sadowski
Molecules 2023, 28(2), 744; https://doi.org/10.3390/molecules28020744 - 11 Jan 2023
Cited by 6 | Viewed by 1482
Abstract
The mechanical properties of ceramic–metal nanocomposites are greatly affected by the equivalent properties of the interface of materials. In this study, the effect of vacancy in SiC on the interdiffusion of SiC/Al interfaces is investigated using the molecular dynamics method. The SiC reinforcements [...] Read more.
The mechanical properties of ceramic–metal nanocomposites are greatly affected by the equivalent properties of the interface of materials. In this study, the effect of vacancy in SiC on the interdiffusion of SiC/Al interfaces is investigated using the molecular dynamics method. The SiC reinforcements exist in the whisker and particulate forms. To this end, cubic and hexagonal SiC lattice polytypes with the Si- and C-terminated interfaces with Al are considered as two samples of metal matrix nanocomposites. The average main and cross-interdiffusion coefficients are determined using a single diffusion couple for each system. The interdiffusion coefficients of the defective SiC/Al are compared with the defect-free SiC/Al system. The effects of temperature, annealing time, and vacancy on the self- and interdiffusion coefficients are investigated. It is found that the interdiffusion of Al in SiC increases with the increase in temperature, annealing time, and vacancy. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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12 pages, 1097 KiB  
Article
Thermal and Electrochemical Properties of Ionic Liquids Bearing Allyl Group with Sulfonate-Based Anions—Application Potential in Epoxy Resin Curing Process
by Andrea Szpecht, Dawid Zielinski, Maciej Galinski and Marcin Smiglak
Molecules 2023, 28(2), 709; https://doi.org/10.3390/molecules28020709 - 10 Jan 2023
Cited by 1 | Viewed by 1653
Abstract
Sulfonate-based ionic liquids (ILs) with allyl-containing cations have been previously obtained by us, however, the present study aims to investigate the thermal, electrochemical and curing properties of these ILs. To determine the temperature range in which ionic liquid maintains a liquid state, thermal [...] Read more.
Sulfonate-based ionic liquids (ILs) with allyl-containing cations have been previously obtained by us, however, the present study aims to investigate the thermal, electrochemical and curing properties of these ILs. To determine the temperature range in which ionic liquid maintains a liquid state, thermal properties must be examined using Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Melting, cold crystallization and glass transition temperatures are discussed, as well as decomposition temperatures for imidazolium- and pyridinium-based ionic liquids. The conductivity and electrochemical stability ranges were studied in order to investigate their potential applicability as electrolytes. Finally, the potential of triflate-based ILs as polymerization initiators for epoxy resins was proven. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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11 pages, 3767 KiB  
Article
Vanadium Ferrocyanides as a Highly Stable Cathode for Lithium-Ion Batteries
by Thang Phan Nguyen and Il Tae Kim
Molecules 2023, 28(2), 461; https://doi.org/10.3390/molecules28020461 - 04 Jan 2023
Cited by 3 | Viewed by 2016
Abstract
Owing to their high redox potential and availability of numerous diffusion channels in metal–organic frameworks, Prussian blue analogs (PBAs) are attractive for metal ion storage applications. Recently, vanadium ferrocyanides (VFCN) have received a great deal of attention for application in sodium-ion batteries, as [...] Read more.
Owing to their high redox potential and availability of numerous diffusion channels in metal–organic frameworks, Prussian blue analogs (PBAs) are attractive for metal ion storage applications. Recently, vanadium ferrocyanides (VFCN) have received a great deal of attention for application in sodium-ion batteries, as they demonstrate a stable capacity with high redox potential of ~3.3 V vs. Na/Na+. Nevertheless, there have been no reports on the application of VFCN in lithium-ion batteries (LIBs). In this work, a facile synthesis of VFCN was performed using a simple solvothermal method under ambient air conditions through the redox reaction of VCl3 with K3[Fe(CN)6]. VFCN exhibited a high redox potential of ~3.7 V vs. Li/Li+ and a reversible capacity of ~50 mAh g–1. The differential capacity plots revealed changes in the electrochemical properties of VFCN after 50 cycles, in which the low spin of Fe ions was partially converted to high spin. Ex situ X-ray diffraction measurements confirmed the unchanged VFCN structure during cycling. This demonstrated the high structural stability of VFCN. The low cost of precursors, simplicity of the process, high stability, and reversibility of VFCN suggest that it can be a candidate for large-scale production of cathode materials for LIBs. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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16 pages, 5006 KiB  
Article
A New Approach to the Synthesis of Nanocrystalline Cobalt Boride in the Course of the Thermal Decomposition of Cobalt Complexes [Co(DMF)6]2+ with Boron Cluster Anions
by Elena A. Malinina, Ivan I. Myshletsov, Grigorii A. Buzanov, Alexey S. Kubasov, Irina V. Kozerozhets, Lyudmila V. Goeva, Svetlana E. Nikiforova, Varvara V. Avdeeva, Konstantin Yu. Zhizhin and Nikolay T. Kuznetsov
Molecules 2023, 28(1), 453; https://doi.org/10.3390/molecules28010453 - 03 Jan 2023
Cited by 9 | Viewed by 2192
Abstract
In the course of the study, nanocrystalline cobalt monoboride was prepared by thermal decomposition of precursors [Co(DMF)6][An], where [An] = [B12H12]2− (1), [trans-B20H18]2− (2) or [...] Read more.
In the course of the study, nanocrystalline cobalt monoboride was prepared by thermal decomposition of precursors [Co(DMF)6][An], where [An] = [B12H12]2− (1), [trans-B20H18]2− (2) or [B10Cl10]2− (3) in an argon atmosphere. Three new salt-like compounds 1–3 were prepared when Co(NO3)2 was allowed to react with (Et3NH)2[An]. Compound 1 is new; the structures of compounds 2 and 3 have been previously reported. Samples 1–3 were annealed at 900 °C in argon to form samples 1a–3a, which were characterized by single crystal XRD for 1 and powder XRD for 1–3. Powder XRD on the products showed the formation of BN and CoB for 1a in a 1:1 ratio; 2a gave a higher CoB:BN ratio but an overall decreased crystallinity. For 3a, only CoB was found. IR spectra of samples 1a–3a as well as X-ray spectral fluorescence analysis for 3a confirmed these results. The nanoparticular character of the decomposition products 1a–3a was shown using TEM; quite small particle sizes of about 10–15 nm and a quite normal size distribution were found for 1a and 2a, while the decomposition of 3 gave large particles with 200–350 nm and a broad distribution. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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24 pages, 4310 KiB  
Article
A DFT Study of Alkaline Earth Metal-Doped FAPbI3 (111) and (100) Surfaces
by Maryam RaeisianAsl, Saeedeh Sarabadani Tafreshi and Nora H. de Leeuw
Molecules 2023, 28(1), 372; https://doi.org/10.3390/molecules28010372 - 02 Jan 2023
Cited by 1 | Viewed by 1643
Abstract
Density functional theory calculations have been performed to study the effect of replacing lead by alkaline earth metals on the stability, electronic and optical properties of the formamidinium lead triiodide (FAPbI3) (111) and (100) surfaces with different terminations in the form [...] Read more.
Density functional theory calculations have been performed to study the effect of replacing lead by alkaline earth metals on the stability, electronic and optical properties of the formamidinium lead triiodide (FAPbI3) (111) and (100) surfaces with different terminations in the form of FAPb1-xAExI3 structures, where AE is Be, Mg or Ca. It is revealed that the (111) surface is more stable, indicating metallic characteristics. The (100) surfaces exhibit a suitable bandgap of around 1.309 and 1.623 eV for PbI5 and PbI6 terminations, respectively. Increases in the bandgaps as a result of Mg- and Ca-doping of the (100) surface were particularly noted in FAPb0.96Ca0.04I3 and FAPb0.8Ca0.2I3 with bandgaps of 1.459 and 1.468 eV, respectively. In the presence of Be, the band gap reduces critically by about 0.315 eV in the FAPb0.95Be0.05I3 structure, while increasing by 0.096 eV in FAPb0.96Be0.04I3. Optimal absorption, high extinction coefficient and light harvesting efficiency were achieved for plain and doped (100) surfaces in the visible and near UV regions. In order to improve the optical properties of the (111)-PbI3 surface in initial visible areas, we suggest calcium-doping in this surface to produce FAPb0.96Ca0.04I3, FAPb0.92Ca0.08I3, and FAPb0.88Ca0.12I3 structures. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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11 pages, 2407 KiB  
Article
Spectrally Selective Full-Color Single-Component Organic Photodetectors Based on Donor-Acceptor Conjugated Molecules
by Artur L. Mannanov, Dmitry O. Balakirev, Elizaveta D. Papkovskaya, Alexander N. Solodukhin, Yuriy N. Luponosov, Dmitry Yu. Paraschuk and Sergey A. Ponomarenko
Molecules 2023, 28(1), 368; https://doi.org/10.3390/molecules28010368 - 02 Jan 2023
Cited by 4 | Viewed by 1811
Abstract
Photodetectors based on organic materials are attractive due to their tunable spectral response and biocompatibility, meaning that they are a promising platform for an artificial human eye. To mimic the photoelectric response of the human eye, narrowband spectrally-selective organic photodetectors are in great [...] Read more.
Photodetectors based on organic materials are attractive due to their tunable spectral response and biocompatibility, meaning that they are a promising platform for an artificial human eye. To mimic the photoelectric response of the human eye, narrowband spectrally-selective organic photodetectors are in great demand, and single-component organic photodetectors based on donor-acceptor conjugated molecules are a noteworthy candidate. In this work, we present single-component selective full-color organic photodetectors based on donor-acceptor conjugated molecules synthetized to mimic the spectral response of the cones and rods of a human eye. The photodetectors demonstrated a high responsivity (up to 70 mA/W) with a response time of less than 1 µs, which is three orders of magnitude faster than that of human eye photoreceptors. Our results demonstrate the possibility of the creation of an artificial eye or photoactive eye “prostheses”. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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18 pages, 13113 KiB  
Article
Gaseous- and Condensed-Phase Activities of Some Reactive P- and N-Containing Fire Retardants in Polystyrenes
by Svetlana Tretsiakova-McNally, Aloshy Baby, Paul Joseph, Doris Pospiech, Eileen Schierz, Albena Lederer, Malavika Arun and Gaëlle Fontaine
Molecules 2023, 28(1), 278; https://doi.org/10.3390/molecules28010278 - 29 Dec 2022
Cited by 2 | Viewed by 1663
Abstract
Polystyrene (PS) was modified by covalently binding P-, P-N- and/or N- containing fire-retardant moieties through co- or ter-polymerization reactions of styrene with diethyl(acryloyloxymethyl)phosphonate (DEAMP), diethyl-p-vinylbenzyl phosphonate (DEpVBP), acrylic acid-2-[(diethoxyphosphoryl)methylamino]ethyl ester (ADEPMAE) and maleimide (MI). In the present study, the condensed-phase and [...] Read more.
Polystyrene (PS) was modified by covalently binding P-, P-N- and/or N- containing fire-retardant moieties through co- or ter-polymerization reactions of styrene with diethyl(acryloyloxymethyl)phosphonate (DEAMP), diethyl-p-vinylbenzyl phosphonate (DEpVBP), acrylic acid-2-[(diethoxyphosphoryl)methylamino]ethyl ester (ADEPMAE) and maleimide (MI). In the present study, the condensed-phase and the gaseous-phase activities of the abovementioned fire retardants within the prepared co- and ter-polymers were evaluated for the first time. Pyrolysis–Gas Chromatography/Mass Spectrometry was employed to identify the volatile products formed during the thermal decomposition of the modified polymers. Benzaldehyde, α-methylstyrene, acetophenone, triethyl phosphate and styrene (monomer, dimer and trimer) were detected in the gaseous phase following the thermal cracking of fire-retardant groups and through main chain scissions. In the case of PS modified with ADEPMAE, the evolution of pyrolysis gases was suppressed by possible inhibitory actions of triethyl phosphate in the gaseous phase. The reactive modification of PS by simultaneously incorporating P- (DEAMP or DEpVBP) and N- (MI) monomeric units, in the chains of ter-polymers, resulted in a predominantly condensed-phase mode of action owing to synergistic P and N interactions. The solid-state 31P NMR spectroscopy, Scanning Electron Microscopy/Energy Dispersive Spectroscopy, Inductively-Coupled Plasma/Optical Emission Spectroscopy and X-ray Photoelectron Spectroscopy of char residues, obtained from ter-polymers, confirmed the retention of the phosphorus species in their structures. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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14 pages, 5947 KiB  
Article
Structural and Electrochemical Properties of Li2O-V2O5-B2O3-Bi2O3 Glass and Glass-Ceramic Cathodes for Lithium-Ion Batteries
by Yuan Chen, Yufei Zhao, Feihong Liu, Mengdie Ding, Juan Wang, Jiuxin Jiang, Pascal Boulet and Marie-Christine Record
Molecules 2023, 28(1), 229; https://doi.org/10.3390/molecules28010229 - 27 Dec 2022
Cited by 3 | Viewed by 1793
Abstract
In this study, 20Li2O-60V2O5-(20 − x)B2O3-xBi2O3 (x = 5, 7.5, 10 mol%) glass materials have been prepared by the melt-quenching method, and the structure and morphology [...] Read more.
In this study, 20Li2O-60V2O5-(20 − x)B2O3-xBi2O3 (x = 5, 7.5, 10 mol%) glass materials have been prepared by the melt-quenching method, and the structure and morphology of the glass materials have been characterized by XRD, FTIR, Raman, and FE-SEM. The results show that the disordered network of the glass is mainly composed of structural motifs, such as VO4, BO3, BiO3, and BiO6. The electrochemical properties of the glass cathode material have been investigated by the galvanostatic charge-discharge method and cyclic voltammetry, and the results show that with the increases of Bi2O3 molar content, the amount of the VO4 group increases, and the network structure of the glass becomes more stable. To further enhance the electrochemical properties, glass-ceramic materials have been obtained by heat treatment, and the effect of the heat treatment temperature on the structure and electrochemical properties of the glass has been studied. The results show that the initial discharge capacity of the glass-ceramic cathode obtained by heat treatment at 280 °C at a current density of 50 mA·g−1 is 333.4 mAh·g−1. In addition, after several cycles of charging and discharging at a high current density of 1000 mA·g−1 and then 10 cycles at 50 mA·g−1, its discharge capacity remains at approximately 300 mAh·g−1 with a capacity retention rate of approximately 90.0%. The results indicate that a proper heat treatment temperature is crucial to improving the electrochemical properties of glass materials. This study provides an approach for the development of new glass cathode materials for lithium-ion batteries. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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15 pages, 4818 KiB  
Article
Deep-Blue Triplet–Triplet Annihilation Organic Light-Emitting Diode (CIEy ≈ 0.05) Using Tetraphenylimidazole and Benzonitrile Functionalized Anthracene/Chrysene Emitters
by Ruttapol Malatong, Wijitra Waengdongbung, Phattananawee Nalaoh, Nuttapong Chantanop, Pongsakorn Chasing, Chokchai Kaiyasuan, Suangsiri Arunlimsawat, Taweesak Sudyoadsuk and Vinich Promarak
Molecules 2022, 27(24), 8923; https://doi.org/10.3390/molecules27248923 - 15 Dec 2022
Cited by 2 | Viewed by 1898
Abstract
Herein, new deep-blue triplet-triplet annihilation (TTA) molecules, namely 4-(10-(4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenyl)anthracen-9-yl)benzonitrile (TPIAnCN) and 4-(12-(4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenyl)chrysen-6-yl)benzonitrile (TPIChCN), are designed, synthesized, and investigated as emitters for organic light-emitting diodes (OLED). TPIAnCN and TPIChCN are composed of polyaromatic hydrocarbons of anthracene (An) and chrysene (Ch) as the cores functionalized [...] Read more.
Herein, new deep-blue triplet-triplet annihilation (TTA) molecules, namely 4-(10-(4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenyl)anthracen-9-yl)benzonitrile (TPIAnCN) and 4-(12-(4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenyl)chrysen-6-yl)benzonitrile (TPIChCN), are designed, synthesized, and investigated as emitters for organic light-emitting diodes (OLED). TPIAnCN and TPIChCN are composed of polyaromatic hydrocarbons of anthracene (An) and chrysene (Ch) as the cores functionalized with tetraphenylimidazole (TPI) and benzonitrile (CN) moieties, respectively. The experimental and theoretical results verify their excellent thermal properties, photophysical properties, as well as electrochemical properties. Particularly, their emissions are in the deep blue region, with TTA emissions being observed in their thin films. By utilization of these molecules as emitters, deep blue TTA OLEDs with CIE coordinates of (0.15, 0.05), high external quantum efficiency of 6.84%, and high exciton utilization efficiency (ηs) of 48% were fabricated. This result manifests the potential use of chrysene as an alternate building block to formulate new TTA molecules for accomplishing high-performance TTA OLEDs. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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14 pages, 4814 KiB  
Article
Desorption of Ammonia Adsorbed on Prussian Blue Analogs by Washing with Saturated Ammonium Hydrogen Carbonate Solution
by Hatsuho Usuda, Yoshie Mishima, Tohru Kawamoto and Kimitaka Minami
Molecules 2022, 27(24), 8840; https://doi.org/10.3390/molecules27248840 - 13 Dec 2022
Cited by 2 | Viewed by 1976
Abstract
Prussian blue analogs (PBAs) have been reported as promising ammonia (NH3) adsorbents with a high capacity compared to activated carbon, zeolite, and ion exchange resins. The adsorbed NH3 was desorbed by heating and washing with water or acid. Recently, we [...] Read more.
Prussian blue analogs (PBAs) have been reported as promising ammonia (NH3) adsorbents with a high capacity compared to activated carbon, zeolite, and ion exchange resins. The adsorbed NH3 was desorbed by heating and washing with water or acid. Recently, we demonstrated that desorption was also possible by washing with a saturated ammonium hydrogen carbonate solution (sat. NH4HCO3aq) and recovered NH3 as an NH4HCO3 solid by introducing CO2 into the washing liquid after desorption. However, this has only been proven for copper ferrocyanide and the relationship between the adsorption/desorption behavior and metal ions in PBAs has not been identified. In this study, we investigated the adsorption/desorption behavior of PBAs that are complexes of first row transition metals with hexacyanometalate anions. Six types of PBAs were tested in this study and copper ferricyanide exhibited the highest desorption/adsorption ratio. X-ray diffraction results revealed high structural stability for cobalt hexacyanocobaltate (CoHCC) and nickel ferricyanide (NiHCF). The Fourier transform infrared spectroscopy results showed that the NH3 adsorbed on the vacancy sites tended to desorb compared to the NH3 adsorbed on the interstitial sites as ammonium ions. Interestingly, the desorption/adsorption ratio exhibited the Irving-Williams order. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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23 pages, 6846 KiB  
Article
Sodium Succinate as a Corrosion Inhibitor for Carbon Steel Rebars in Simulated Concrete Pore Solution
by Ahmed Mohamed, Donald P. Visco, Jr. and David M. Bastidas
Molecules 2022, 27(24), 8776; https://doi.org/10.3390/molecules27248776 - 10 Dec 2022
Cited by 3 | Viewed by 1929
Abstract
The inhibiting performance of sodium succinate (Na2C4H4O4) was evaluated as an organic environmentally friendly corrosion inhibitor for carbon steel rebars in 0.6 M Cl− simulated concrete pore solution. Potentiodynamic polarization (PDP) and electrochemical impedance [...] Read more.
The inhibiting performance of sodium succinate (Na2C4H4O4) was evaluated as an organic environmentally friendly corrosion inhibitor for carbon steel rebars in 0.6 M Cl− simulated concrete pore solution. Potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) measurements were utilized to evaluate the inhibitor performance at different temperatures and concentrations. The investigated corrosion inhibitor showed strong corrosion inhibition performance as it adsorbs on the surface of the rebar, creating a protective adsorption film. According to PDP, the inhibitor is classified as a mixed-type inhibitor with an inhibitor efficiency of 77, 69, 59, and 54% for 25, 35, 45, and 55 °C, respectively. EIS validated the PDP tests, showing that sodium succinate displaces the water molecules at the interface, creating an adsorption film by complexing with ferrous ions. The film thickness was calculated, and sodium succinate was able to produce a thicker protective film (span of nanometers) relative to the reference at every temperature. The adsorption of sodium succinate follows the Temkin adsorption isotherm. ΔG0ads was found to be −32.75 kJ/mol, indicating that the inhibitor adsorption is a combined physisorption and chemisorption process. Different surface characterizations were utilized to substantiate the adsorption of sodium succinate, these include scanning electron microscopy, energy-dispersive X-ray spectroscopy, and micro-Raman spectroscopy. Finally, quantum chemical calculations showed that the delocalized electrons in the carboxyl group have high HOMO energies and electrostatic potential, which facilitates the adsorption of sodium succinate corrosion inhibitor onto the carbon steel rebar surface. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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10 pages, 2212 KiB  
Article
Toward High-Energy-Density Aqueous Lithium-Ion Batteries Using Silver Nanowires as Current Collectors
by Jingyi Kong, Yangyang Wang, Ying Wu, Liang Zhang, Min Gong, Xiang Lin and Dongrui Wang
Molecules 2022, 27(23), 8207; https://doi.org/10.3390/molecules27238207 - 25 Nov 2022
Cited by 3 | Viewed by 1469
Abstract
The lack of suitable lightweight current collectors is one of the primary obstacles preventing the energy density of aqueous lithium-ion batteries (ALIBs) from becoming competitive. Using silver nanowire (AgNW) films as current collectors and a molecular crowding electrolyte, we herein report the fabrication [...] Read more.
The lack of suitable lightweight current collectors is one of the primary obstacles preventing the energy density of aqueous lithium-ion batteries (ALIBs) from becoming competitive. Using silver nanowire (AgNW) films as current collectors and a molecular crowding electrolyte, we herein report the fabrication of ALIBs with relatively good energy densities. In the 2 m LiTFSI–94% PEG–6% H2O solution, the AgNW films with a sheet resistance of less than 1.0 ohm/square exhibited an electrochemical stability window as broad as 3.8 V. The LiMn2O4//Li4Ti5O12 ALIBs using AgNW films as the current collectors demonstrated an initial energy density of 70 Wh/kg weighed by the total mass of the cathode and anode, which retained 89.1% after 50 cycles. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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18 pages, 5418 KiB  
Article
Analysis of Adhesion at the Interface of Steamed Bread and Eggshell
by Qunfeng Zeng and Jianing Zhu
Molecules 2022, 27(23), 8179; https://doi.org/10.3390/molecules27238179 - 24 Nov 2022
Viewed by 1258
Abstract
The adhesion phenomenon of polymers occurs in nature and in human activity. In the present paper, an adhesion system of steamed bread and eggshell was observed in formation when steamed bread and eggshells were placed in close contact and cooled slightly in the [...] Read more.
The adhesion phenomenon of polymers occurs in nature and in human activity. In the present paper, an adhesion system of steamed bread and eggshell was observed in formation when steamed bread and eggshells were placed in close contact and cooled slightly in the ambient air. The adhesion phenomena and mechanism of the adhesion interface between the steamed bread and eggshell were investigated and systematically discussed. Strong-bond interfaces were observed by scanning electron microscope (SEM). The formation process and mechanism of the strong-bond adhesion were also analyzed molecular dynamics simulation technology, and the results are discussed. The simulation analyses showed that the starch molecules at the calcite (104) crystal face were diffused in a water vapor environment, and the formation and solidification of multiple hydrogen bonds in the starch chain and oxygen atoms in the calcium carbonate were observed in detail during cooling. The diffusion rate of hydrogen atoms in hydroxyl groups on the calcite surface decreased gradually with the decrease of the cooling temperature of the steamed bread’s upper surface. The strong adhesion of the steamed bread and eggshell is attributed to the synthetic effect of the absorption, diffusion, surface chemistry, and the formation of multiple hydrogen bonds between the starch from the steamed bread and the calcium carbonate crystals in eggshell. The interesting findings are helpful for the design of strong bonds, and provide an idea for new environmentally friendly adhesive materials. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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14 pages, 4323 KiB  
Article
Effects of Through-Bond and Through-Space Conjugations on the Photoluminescence of Small Aromatic and Aliphatic Aldimines
by Peifeng Zhuang, Chang Yuan, Yunhao Bai, Changcheng He, Jiayu Long, Hongwei Tan and Huiliang Wang
Molecules 2022, 27(22), 8046; https://doi.org/10.3390/molecules27228046 - 19 Nov 2022
Cited by 5 | Viewed by 1724
Abstract
Through-bond conjugation (TBC) and/or through-space conjugation (TSC) determine the photophysical properties of organic luminescent compounds. No systematic studies have been carried out to understand the transition from aromatic TBC to non-aromatic TSC on the photoluminescence of organic luminescent compounds. In this work, a [...] Read more.
Through-bond conjugation (TBC) and/or through-space conjugation (TSC) determine the photophysical properties of organic luminescent compounds. No systematic studies have been carried out to understand the transition from aromatic TBC to non-aromatic TSC on the photoluminescence of organic luminescent compounds. In this work, a series of small aromatic and aliphatic aldimines were synthesized. For the aromatic imines, surprisingly, N,1-diphenylmethanimine with the highest TBC is non-emissive, while N-benzyl-1-phenylmethanimine and N-cyclohexyl-1-phenylmethanimine emit bright fluorescence in aggregate states. The aliphatic imines are all emissive, and their maximum emission wavelength decreases while the quantum yield increases with a decrease in steric hindrance. The imines show concentration-dependent and excitation-dependent emissions. Theoretical calculations show that the TBC extents in the aromatic imines are not strong enough to induce photoluminescence in a single molecule state, while the intermolecular TSC becomes dominant for the fluorescence emissions of both aromatic and aliphatic imines in aggregate states, and the configurations and spatial conformations of the molecules in aggregate states play a key role in the formation of effective TSC. This study provides an understanding of how chemical and spatial structures affect the formation of TBC and TSC and their functions on the photoluminescence of organic luminescent materials. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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19 pages, 2266 KiB  
Article
Nitrogen-Doped Titanium Dioxide as a Hole Transport Layer for High-Efficiency Formamidinium Perovskite Solar Cells
by Nitin Ralph Pochont, Yendaluru Raja Sekhar, Kuraganti Vasu and Rajan Jose
Molecules 2022, 27(22), 7927; https://doi.org/10.3390/molecules27227927 - 16 Nov 2022
Cited by 4 | Viewed by 1795
Abstract
Perovskite solar cells (PSCs) offer advantages over widely deployed silicon solar cells in terms of ease of fabrication; however, the device is still under rigorous materials optimization for cell performance, stability, and cost. In this work, we explore a version of a PSC [...] Read more.
Perovskite solar cells (PSCs) offer advantages over widely deployed silicon solar cells in terms of ease of fabrication; however, the device is still under rigorous materials optimization for cell performance, stability, and cost. In this work, we explore a version of a PSC by replacing the polymeric hole transport layer (HTL) such as Spiro-OMeTAD, P3HT, and PEDOT: PSS with a more air-stable metal oxide, viz., nitrogen-doped titanium dioxide (TiO2:N). Numerical simulations on formamidinium (FA)-based PSCs in the FTO/TiO2/FAPbI3/Ag configuration have been carried out to depict the behaviour of the HTL as well as the effect of absorber layer thickness (∆t) on photovoltaic parameters. The results show that the cell output increases when the HTL bandgap increases from 2.5 to 3.0 eV. By optimizing the absorber layer thickness and the gradient in defect density (Nt), the device structure considered here can deliver a maximum power conversion efficiency of ~21.38% for a lower HTL bandgap (~2.5 eV) and ~26.99% for a higher HTL bandgap of ~3.0 eV. The results are validated by reproducing the performance of PSCs employing commonly used polymeric HTLs, viz. Spiro-OMeTAD, P3HT, and PEDOT: PSS as well as high power conversion efficiency in the highly crystalline perovskite layer. Therefore, the present study provides high-performing, cost-effective PSCs using TiO2:N. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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9 pages, 2039 KiB  
Article
Straightforward Approach for Preparing Durable Antibacterial ZnO Nanoparticle Coatings on Flexible Substrates
by Andris Šutka, Linda Mežule, Viktorija Denisova, Jochen Meier-Haack, Akshay Kulkarni, Sanda Bitina, Krisjanis Smits and Svetlana Vihodceva
Molecules 2022, 27(22), 7672; https://doi.org/10.3390/molecules27227672 - 08 Nov 2022
Cited by 1 | Viewed by 1418
Abstract
Flexible antibacterial materials have gained utmost importance in protection from the distribution of bacteria and viruses due to the exceptional variety of applications. Herein, we demonstrate a readily scalable and rapid single-step approach for producing durable ZnO nanoparticle antibacterial coating on flexible polymer [...] Read more.
Flexible antibacterial materials have gained utmost importance in protection from the distribution of bacteria and viruses due to the exceptional variety of applications. Herein, we demonstrate a readily scalable and rapid single-step approach for producing durable ZnO nanoparticle antibacterial coating on flexible polymer substrates at room temperature. Substrates used are polystyrene, poly(ethylene-co-vinyl acetate) copolymer, poly(methyl methacrylate), polypropylene, high density polyethylene and a commercial acrylate type adhesive tape. The deposition was achieved by a spin-coating process using a slurry of ZnO nanoparticles in toluene. A stable modification layer was obtained when toluene was a solvent for the polymer substrates, namely polystyrene and poly(ethylene-co-vinyl acetate). These coatings show high antibacterial efficiency causing >5 log decrease in the viable counts of Gram-negative bacteria Escherichia. coli and Gram-positive bacteria Staphylococcus aureus in 120 min. Even after tapping these coated surfaces 500 times, the antibacterial properties remained unchanged, showing that the coating obtained by the presented method is very robust. In contrast to the above findings, the coatings are unstable when toluene is not a solvent for the substrate. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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16 pages, 4594 KiB  
Article
Novel In Situ Growth of ZIF-8 in Porous Epoxy Matrix for Mechanically Robust Composite Electrolyte of High-Performance, Long-Life Lithium Metal Batteries
by Wenjie Zhang, Jianlin Long, Haijun Wang, Jinle Lan, Yunhua Yu and Xiaoping Yang
Molecules 2022, 27(21), 7488; https://doi.org/10.3390/molecules27217488 - 03 Nov 2022
Cited by 4 | Viewed by 1905
Abstract
Polymer electrolytes (PEs) with high flexibility, low cost, and excellent interface compatibility have been considered as an ideal substitute for traditional liquid electrolytes for high safety lithium metal batteries (LMBs). Nevertheless, the mechanical strength of PEs is generally poor to prevent the growth [...] Read more.
Polymer electrolytes (PEs) with high flexibility, low cost, and excellent interface compatibility have been considered as an ideal substitute for traditional liquid electrolytes for high safety lithium metal batteries (LMBs). Nevertheless, the mechanical strength of PEs is generally poor to prevent the growth of lithium dendrites during the charge/discharge process, which seriously restricts their wide practical applications. Herein, a mechanical robust ZIF-8/epoxy composite electrolyte with unique pore structure was prepared, which effectively inhibited the growth of lithium dendrites. Meanwhile, the in situ growth of ZIF-8 in porous epoxy matrix can promote the uniform flux and fast transport of lithium ions. Ultimately, the optimal electrolyte shows high ionic conductivity (2.2 × 10−3 S cm−1), wide electrochemical window (5 V), and a large Li+ transference number (0.70) at room temperature. The Li||NCM811 cell using the optimal electrolyte exhibits high capacity and excellent cycling performance (83.2% capacity retention with 172.1 mA h g−1 capacity retained after 200 cycles at 0.2 C). These results indicate that the ZIF-8/epoxy composite electrolyte is of great promise for the application in LMBs. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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14 pages, 2395 KiB  
Article
High-Temperature Magnesiothermic Reduction Enables HF-Free Synthesis of Porous Silicon with Enhanced Performance as Lithium-Ion Battery Anode
by Xiuxia Zuo, Qinghua Yang, Yaolong He, Ya-Jun Cheng, Shanshan Yin, Jin Zhu, Peter Müller-Buschbaum and Yonggao Xia
Molecules 2022, 27(21), 7486; https://doi.org/10.3390/molecules27217486 - 02 Nov 2022
Cited by 3 | Viewed by 2132
Abstract
Porous silicon-based anode materials have gained much interest because the porous structure can effectively accommodate volume changes and release mechanical stress, leading to improved cycling performance. Magnesiothermic reduction has emerged as an effective way to convert silica into porous silicon with a good [...] Read more.
Porous silicon-based anode materials have gained much interest because the porous structure can effectively accommodate volume changes and release mechanical stress, leading to improved cycling performance. Magnesiothermic reduction has emerged as an effective way to convert silica into porous silicon with a good electrochemical performance. However, corrosive HF etching is normally a mandatory step to improve the electrochemical performance of the as-synthesized silicon, which significantly increases the safety risk. This has become one of the major issues that impedes practical application of the magnesiothermic reduction synthesis of the porous silicon anode. Here, a facile HF-free method is reported to synthesize macro-/mesoporous silicon with good cyclic and rate performance by simply increasing the reduction temperature from 700 °C to 800 °C and 900 °C. The mechanism for the structure change resulting from the increased temperature is elaborated. A finite element simulation indicated that the 3D continuous structure formed by the magnesiothermic reduction at 800 °C and 900 °C could undertake the mechanical stress effectively and was responsible for an improved cyclic stability compared to the silicon synthesized at 700 °C. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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18 pages, 4385 KiB  
Article
Distinct Antifouling Mechanisms on Different Chain Densities of Zwitterionic Polymers
by Clil Regev, Zhongyi Jiang, Roni Kasher and Yifat Miller
Molecules 2022, 27(21), 7394; https://doi.org/10.3390/molecules27217394 - 31 Oct 2022
Cited by 1 | Viewed by 1249
Abstract
Antifouling polymer coating surfaces are used in widespread industries applications. Zwitterionic polymers have been identified as promising materials in developing polymer coating surfaces. Importantly, the density of the polymer chains is crucial for acquiring superior antifouling performance. This study introduces two different zwitterionic [...] Read more.
Antifouling polymer coating surfaces are used in widespread industries applications. Zwitterionic polymers have been identified as promising materials in developing polymer coating surfaces. Importantly, the density of the polymer chains is crucial for acquiring superior antifouling performance. This study introduces two different zwitterionic polymer density surfaces by applying molecular modeling tools. To assess the antifouling performance, we mimic static adsorption test, by placing the foulant model bovine serum albumin (BSA) on the surfaces. Our findings show that not only the density of the polymer chain affect antifouling performance, but also the initial orientation of the BSA on the surface. Moreover, at a high-density surface, the foulant either detaches from the surface or anchor on the surface. At low-density surface, the foulant does not detach from the surface, but either penetrates or anchors on the surface. The anchoring and the penetrating mechanisms are elucidated by the electrostatic interactions between the foulant and the surface. While the positively charged ammonium groups of the polymer play major role in the interactions with the negatively charged amino acids of the BSA, in the penetrating mechanism the ammonium groups play minor role in the interactions with the contact with the foulant. The sulfonate groups of the polymer pull the foulant in the penetrating mechanism. Our work supports the design of a high-density polymer chain surface coating to prevent fouling phenomenon. Our study provides for the first-time insights into the molecular mechanism by probing the interactions between BSA and the zwitterion surface, while testing high- and low-densities polymer chains. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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20 pages, 3532 KiB  
Article
Microplastic-Free Microcapsules to Encapsulate Health-Promoting Limonene Oil
by Daniele Baiocco and Zhibing Zhang
Molecules 2022, 27(21), 7215; https://doi.org/10.3390/molecules27217215 - 25 Oct 2022
Cited by 3 | Viewed by 1741
Abstract
Fast-moving consumer goods (FMCG) industry has long included many appealing essential oils in products to meet consumers’ needs. Among all, the demand for limonene (LM) has recently surged due to its broad-spectrum health benefits, with applications in cosmetic, detergent, and food products. However, [...] Read more.
Fast-moving consumer goods (FMCG) industry has long included many appealing essential oils in products to meet consumers’ needs. Among all, the demand for limonene (LM) has recently surged due to its broad-spectrum health benefits, with applications in cosmetic, detergent, and food products. However, LM is extremely volatile, hence has often been encapsulated for a longer shelf-life. To date, mostly non-biodegradable synthetic polymers have been exploited to fabricate the microcapsule shells, and the resulting microcapsules contribute to the accumulation of microplastic in the environment. So far, information on LM-entrapping microcapsules with a natural microplastic-free shell and their mechanism of formation is limited, and there is lack of an in-depth characterisation of their mechanical and adhesive properties, which are crucial for understanding their potential performance at end-use applications. The present research aims towards developing safe microcapsules with a core of LM fabricated via complex coacervation (CC) using gum Arabic (GA) and fungally sourced chitosan (fCh) as shell precursors. The encapsulation efficiency (EE) for LM was quantified by gas chromatography (GC) separation method. The morphology of microcapsules was investigated via bright-field optical microscopy and scanning electron microscopy, and their mechanical properties were characterised using a micromanipulation technique. Moreover, the adhesive properties of the resulting microcapsules were studied via a bespoke microfluidic device fitted with a polyethylene-terephthalate (PET) substrate and operating at increasingly hydrodynamic shear stress (HSS). Spherical core-shell microcapsules (EE ~45%) with a mean size of 38 ± 2 μm and a relatively smooth surface were obtained. Their mean rupture force and nominal rupture stress were 0.9 ± 0.1 mN and 2.1 ± 0.2 MPa, respectively, which are comparable to those of other microcapsules with synthetic shells, e.g., urea- and melamine-formaldehyde. It was also found that the fCh-GA complexed shell provided promising adhesive properties onto PET films, leading to a microcapsule retention of ~85% and ~60% at low (≤50 mPa) and high shear stress (0.9 Pa), respectively. Interestingly, these values are similar to the adhesion data available in literature for microplastic-based microcapsules, such as melamine-formaldehyde (50–90%). Overall, these findings suggest that microplastics-free microcapsules with a core of oil have been successfully fabricated, and can offer a potential for more sustainable, consumer- and environmentally friendly applications in FMCGs. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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12 pages, 4187 KiB  
Article
ZnO/Boron Nitride Quantum Dots Nanocomposites for the Enhanced Photocatalytic Degradation of Methylene Blue and Methyl Orange
by Di Liu, Jinu Song, Jin Suk Chung, Seung Hyun Hur and Won Mook Choi
Molecules 2022, 27(20), 6833; https://doi.org/10.3390/molecules27206833 - 12 Oct 2022
Cited by 13 | Viewed by 1501
Abstract
In this study, a heterostructure photocatalyst of ZnO nanoparticles decorated with boron nitride quantum dots (ZnO/BNQDs) was successfully synthesized by a simple solution procedure. The synthesized ZnO/BNQDs show that the BNQDs effectively suppress the recombination of photoinduced electrons and holes and the transfer [...] Read more.
In this study, a heterostructure photocatalyst of ZnO nanoparticles decorated with boron nitride quantum dots (ZnO/BNQDs) was successfully synthesized by a simple solution procedure. The synthesized ZnO/BNQDs show that the BNQDs effectively suppress the recombination of photoinduced electrons and holes and the transfer of holes from ZnO nanoparticles by the formation of a heterojunction. The ZnO/BNQD nanocomposites thus demonstrate superior photocatalytic performances and excellent stability for the degradation of methylene blue (MB) and methyl orange (MO) under UV light irradiation. Based on the obtained results, the possible photocatalytic mechanism is proposed and discussed. Thus, the ZnO/BNQD nanocomposites demonstrate potential as an efficient low-cost photocatalyst for application in the photodegradation of organic dyes in wastewater for environmental remediation. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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15 pages, 2973 KiB  
Article
Synthesis and Characterization of Newly Designed and Highly Solvatochromic Double Squaraine Dye for Sensitive and Selective Recognition towards Cu2+
by Linjun Tang, Shubham Sharma and Shyam S. Pandey
Molecules 2022, 27(19), 6578; https://doi.org/10.3390/molecules27196578 - 04 Oct 2022
Cited by 6 | Viewed by 1630
Abstract
Synthesis and characterization of a novel and zwitterionic double squaraine dye (DSQ) with a unique D-A-A-D structure is being reported. Contrary to the conventional mono and bis-squaraine dyes with D-A-D and D-A-D-A molecular frameworks reported so far, DSQ dye demonstrated strong solvatochromism allowing [...] Read more.
Synthesis and characterization of a novel and zwitterionic double squaraine dye (DSQ) with a unique D-A-A-D structure is being reported. Contrary to the conventional mono and bis-squaraine dyes with D-A-D and D-A-D-A molecular frameworks reported so far, DSQ dye demonstrated strong solvatochromism allowing for the multiple ion sensing using a single probe by judicious selection of the suitable solvent system. The DSQ dye exhibited a large solvatochromic shift of about 200 nm with color changes from the visible to NIR region with metal ion sensitivity. Utilization of a binary solvent consisted of dimethylformamide and acetonitrile (1:99, v/v), highly selective detection of Cu2+ ions with the linearity range from 50 μM to 1 nM and a detection limit of 6.5 × 10−10 M has been successfully demonstrated. Results of the Benesi–Hildebrand and Jobs plot analysis revealed that DSQ and Cu2+ ions interact in the 2:1 molecular stoichiometry with appreciably good association constant of 2.32 × 104 M−1. Considering the allowed limit of Cu2+ ions intake by human body as recommended by WHO to be 30 μM, the proposed dye can be conveniently used for the simple and naked eye colorimetric monitoring of the drinking water quality. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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13 pages, 2400 KiB  
Article
Cobalt Incorporated Graphitic Carbon Nitride as a Bifunctional Catalyst for Electrochemical Water-Splitting Reactions in Acidic Media
by Shibiru Yadeta Ejeta and Toyoko Imae
Molecules 2022, 27(19), 6445; https://doi.org/10.3390/molecules27196445 - 30 Sep 2022
Cited by 11 | Viewed by 1569
Abstract
Non-noble metal-based bifunctional electrocatalysts may be a promising new resource for electrocatalytic water-splitting devices. In this work, transition metal (cobalt)-incorporated graphitic carbon nitride was synthesized and fabricated in electrodes for use as bifunctional catalysts. The optimum catalytic activity of this bifunctional material for [...] Read more.
Non-noble metal-based bifunctional electrocatalysts may be a promising new resource for electrocatalytic water-splitting devices. In this work, transition metal (cobalt)-incorporated graphitic carbon nitride was synthesized and fabricated in electrodes for use as bifunctional catalysts. The optimum catalytic activity of this bifunctional material for the hydrogen evolution reaction (HER), which benefitted at a cobalt content of 10.6 wt%, was promoted by the highest surface area and conductivity. The activity achieved a minimum overpotential of ~85 mV at 10 mA/cm2 and a Tafel slope of 44.2 mV/dec in an acidic electrolyte. These values of the HER were close to those of a benchmark catalyst (platinum on carbon paper electrode). Moreover, the kinetics evaluation at the optimum catalyst ensured the catalyst flows (Volmer–Heyrovsky mechanism), indicating that the adsorption step is rate-determining for the HER. The activity for the oxygen evolution reaction (OER) indicated an overpotential of ~530 mV at 10 mAcm−2 and a Tafel slope of 193.3 mV/dec, which were slightly less or nearly the same as those of the benchmark catalyst. Stability tests using long-term potential cycles confirmed the high durability of the catalyst for both HER and OER. Moreover, the optimal bifunctional catalyst achieved a current density of 10 mAcm−2 at a cell voltage of 1.84 V, which was slightly less than that of the benchmark catalyst (1.98 V). Thus, this research reveals that the present bifunctional, non-noble metallic electrocatalyst is adequate for use as a water-splitting technology in acidic media. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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24 pages, 4063 KiB  
Article
Structural Dynamics, Phonon Spectra and Thermal Transport in the Silicon Clathrates
by Benxiang Wei, Joseph M. Flitcroft and Jonathan M. Skelton
Molecules 2022, 27(19), 6431; https://doi.org/10.3390/molecules27196431 - 29 Sep 2022
Cited by 3 | Viewed by 1519
Abstract
The potential of thermoelectric power to reduce energy waste and mitigate climate change has led to renewed interest in “phonon-glass electron-crystal” materials, of which the inorganic clathrates are an archetypal example. In this work we present a detailed first-principles modelling study of the [...] Read more.
The potential of thermoelectric power to reduce energy waste and mitigate climate change has led to renewed interest in “phonon-glass electron-crystal” materials, of which the inorganic clathrates are an archetypal example. In this work we present a detailed first-principles modelling study of the structural dynamics and thermal transport in bulk diamond Si and five framework structures, including the reported Si Clathrate I and II structures and the recently-synthesised oC24 phase, with a view to understanding the relationship between the structure, lattice dynamics, energetic stability and thermal transport. We predict the IR and Raman spectra, including ab initio linewidths, and identify spectral signatures that could be used to confirm the presence of the different phases in material samples. Comparison of the energetics, including the contribution of the phonons to the finite-temperature Helmholtz free energy, shows that the framework structures are metastable, with the energy differences to bulk Si dominated by differences in the lattice energy. Thermal-conductivity calculations within the single-mode relaxation-time approximation show that the framework structures have significantly lower κlatt than bulk Si, which we attribute quantitatively to differences in the phonon group velocities and lifetimes. The lifetimes vary considerably between systems, which can be largely accounted for by differences in the three-phonon interaction strengths. Notably, we predict a very low κlatt for the Clathrate-II structure, in line with previous experiments but contrary to other recent modelling studies, which motivates further exploration of this system. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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19 pages, 2737 KiB  
Article
Phosphorus Modified Cardanol: A Greener Route to Reduce VolaTile Organic Compounds and Impart Flame Retardant Properties to Alkyd Resin Coatings
by Maxinne Denis, Damien Le Borgne, Rodolphe Sonnier, Sylvain Caillol, Cédric Totee and Claire Negrell
Molecules 2022, 27(15), 4880; https://doi.org/10.3390/molecules27154880 - 30 Jul 2022
Cited by 1 | Viewed by 2024
Abstract
Novel phosphorylated cardanol molecules based on phosphonate (PO3CR) and phosphate (PO4CR) functions were synthetized. Those molecules have two main actions which are described in this article: the reduction in volatile organic compounds (VOC) and the development of flame retardant [...] Read more.
Novel phosphorylated cardanol molecules based on phosphonate (PO3CR) and phosphate (PO4CR) functions were synthetized. Those molecules have two main actions which are described in this article: the reduction in volatile organic compounds (VOC) and the development of flame retardant (FR) properties conferred on alkyd resins used as coatings for wood specimen. Phosphorylated cardanol compounds have been successfully grafted by covalent bonds to alkyd resins thanks to an auto-oxidative reaction. The impact of the introduction of PO3CR and PO4CR on the film properties such as drying time and flexibility has been studied and the thermal and flame retardant properties through differential scanning calorimeter, thermogravimetric analysis and pyrolysis-combustion flow calorimeter. These studies underscored an increase in the thermal stability and FR properties of the alkyd resins. In the cone calorimeter test, the lowest pHRR was obtained with 3 wt% P of phosphate-cardanol and exhibited a value of 170 KW.m−2, which represented a decrease of almost 46% compared to the POxCR-free alkyd resins. Moreover, a difference in the mode of action between phosphonate and phosphate compounds has been highlighted. The most effective coating which combined excellent FR properties and good coating properties has been obtained with 2 wt% P of phosphate-cardanol. Indeed, the film properties were closed to the POxCR-free alkyd resin and the pHRR decreased by 41% compared to the reference alkyd resin. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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17 pages, 2401 KiB  
Article
Study of the Antioxidative Effects of Bombyx mori Silk Sericin in Cultures of Murine Retinal Photoreceptor Cells
by Shuko Suzuki, Onur Sakiragaoglu and Traian V. Chirila
Molecules 2022, 27(14), 4635; https://doi.org/10.3390/molecules27144635 - 20 Jul 2022
Cited by 5 | Viewed by 1761
Abstract
The availability of natural substances able to fulfill the role of antioxidants in a physiologic environment is important for the development of therapies against diseases associated with excessive production of reactive oxygen species and ensuing oxidative stress. Antioxidant properties have been reported episodically [...] Read more.
The availability of natural substances able to fulfill the role of antioxidants in a physiologic environment is important for the development of therapies against diseases associated with excessive production of reactive oxygen species and ensuing oxidative stress. Antioxidant properties have been reported episodically for sericin, a proteinaceous constituent of the silk thread in the cocoons generated by the larvae of the Lepidoptera order. We investigated the sericin fractions isolated from the cocoons spun by the domesticated (Bombyx mori) silkworm. Three fractions were isolated and evaluated, including two peptidoid fractions, the crude sericin and the purified (dialyzed) sericin, and the non-peptidoid methanolic extract of the crude fraction. When subjected to Trolox equivalent antioxidant capacity (TEAC) assay, the extract showed much higher antioxidant capacity as compared to the crude or purified sericin fractions. The three fractions were also evaluated in cultures of murine retinal photoreceptor cells (661 W), a cell line that is highly susceptible to oxidants and is crucially involved in the retinopathies primarily caused by oxidative stress. The extract displayed a significant dose-dependent protective effect on the cultured cells exposed to hydrogen peroxide. In identical conditions, the crude sericin showed a certain level of antioxidative activity at a higher concentration, while the purified sericin did not show any activity. We concluded that the non-peptidoid components accompanying sericin were chiefly responsible for the previously reported antioxidant capacity associated with sericin fractions, a conclusion supported by the qualitative detection of flavonoids in the extract but not in the purified sericin fraction. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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11 pages, 2017 KiB  
Article
Peptide-Functionalized Silk Fibers as a Platform to Stabilize Gelatin for Use in Ingestible Devices
by Luca Valentini, Lorenzo Pacini, Fosca Errante, Cecilia Morchio, Beatrice Sanna, Paolo Rovero and Antonino Morabito
Molecules 2022, 27(14), 4605; https://doi.org/10.3390/molecules27144605 - 19 Jul 2022
Cited by 2 | Viewed by 1648
Abstract
The combination of pharmacologic and endoscopic therapies is the gold standard for treating intestinal failures. The possibility of chemical solubility in water is mandatory for intelligent capsules. Functionalised silk fibroin with peptides and covalently linking different molecular entities to its structure make this [...] Read more.
The combination of pharmacologic and endoscopic therapies is the gold standard for treating intestinal failures. The possibility of chemical solubility in water is mandatory for intelligent capsules. Functionalised silk fibroin with peptides and covalently linking different molecular entities to its structure make this protein a platform for preparing gels dissolving in the small and large intestine for drug delivery. In the present study, we linked a peptide containing the cell-adhesive motif Arginine–Glycine–Aspartic acid (RGD) to degummed silk fibres (DSF). Regenerated silk fibroin (RS) films obtained by dissolving functionalised DSF in formic acid were used to prepare composite gelatin. We show that such composite gelatin remains stable and elastic in the simulated gastric fluid (SGF) but can dissolve in the small and large intestines’ neutral-pH simulated intestine fluid (SIF). These findings open up the possibility of designing microfabricated and physically programmable scaffolds that locally promote tissue regeneration, thanks to bio-enabled materials based on functionalised regenerated silk. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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Review

Jump to: Research

25 pages, 9692 KiB  
Review
Self-Assembled Monolayers of Push–Pull Chromophores as Active Layers and Their Applications
by Junlong Wang, Virginie Gadenne, Lionel Patrone and Jean-Manuel Raimundo
Molecules 2024, 29(3), 559; https://doi.org/10.3390/molecules29030559 - 23 Jan 2024
Viewed by 846
Abstract
In recent decades, considerable attention has been focused on the design and development of surfaces with defined or tunable properties for a wide range of applications and fields. To this end, self-assembled monolayers (SAMs) of organic compounds offer a unique and straightforward route [...] Read more.
In recent decades, considerable attention has been focused on the design and development of surfaces with defined or tunable properties for a wide range of applications and fields. To this end, self-assembled monolayers (SAMs) of organic compounds offer a unique and straightforward route of modifying and engineering the surface properties of any substrate. Thus, alkane-based self-assembled monolayers constitute one of the most extensively studied organic thin-film nanomaterials, which have found wide applications in antifouling surfaces, the control of wettability or cell adhesion, sensors, optical devices, corrosion protection, and organic electronics, among many other applications, some of which have led to their technological transfer to industry. Nevertheless, recently, aromatic-based SAMs have gained importance as functional components, particularly in molecular electronics, bioelectronics, sensors, etc., due to their intrinsic electrical conductivity and optical properties, opening up new perspectives in these fields. However, some key issues affecting device performance still need to be resolved to ensure their full use and access to novel functionalities such as memory, sensors, or active layers in optoelectronic devices. In this context, we will present herein recent advances in π-conjugated systems-based self-assembled monolayers (e.g., push–pull chromophores) as active layers and their applications. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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27 pages, 5010 KiB  
Review
From Visible to Near–Infrared Light–Triggered Photochromism: Negative Photochromism
by Ruiji Li, Bingzhao Mou, Mihoko Yamada, Wei Li, Takuya Nakashima and Tsuyoshi Kawai
Molecules 2024, 29(1), 155; https://doi.org/10.3390/molecules29010155 - 26 Dec 2023
Viewed by 1194
Abstract
Photochromic compounds, whose key molecular properties can be effectively modulated by light irradiation, have attracted significant attention for their potential applications in various research fields. The restriction of photoisomerization coloration induced by ultraviolet light limits their applications in the biomedical field and some [...] Read more.
Photochromic compounds, whose key molecular properties can be effectively modulated by light irradiation, have attracted significant attention for their potential applications in various research fields. The restriction of photoisomerization coloration induced by ultraviolet light limits their applications in the biomedical field and some other fields. Negative photochromism, wherein a relatively stable colored isomer transforms to a colorless metastable isomer under low–energy light irradiation, offers advantages in applications within materials science and life science. This review provides a summary of negatively photochromic compounds based on different molecular skeletons. Their corresponding design strategies and photochromic properties are presented to provide practical guidelines for future investigations. Negatively photochromic compounds can effectively expand the range of photochromic switches for future applications, offering unique properties such as responsiveness to visible to near–infrared light. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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26 pages, 5401 KiB  
Review
Recent Advances in Graphitic Carbon Nitride Based Electro-Catalysts for CO2 Reduction Reactions
by Xinyi Mao, Ruitang Guo, Quhan Chen, Huiwen Zhu, Hongzhe Li, Zijun Yan, Zeyu Guo and Tao Wu
Molecules 2023, 28(8), 3292; https://doi.org/10.3390/molecules28083292 - 07 Apr 2023
Cited by 5 | Viewed by 2092
Abstract
The electrocatalytic carbon dioxide reduction reaction is an effective means of combating the greenhouse effect caused by massive carbon dioxide emissions. Carbon nitride in the graphitic phase (g-C3N4) has excellent chemical stability and unique structural properties that allow it [...] Read more.
The electrocatalytic carbon dioxide reduction reaction is an effective means of combating the greenhouse effect caused by massive carbon dioxide emissions. Carbon nitride in the graphitic phase (g-C3N4) has excellent chemical stability and unique structural properties that allow it to be widely used in energy and materials fields. However, due to its relatively low electrical conductivity, to date, little effort has been made to summarize the application of g-C3N4 in the electrocatalytic reduction of CO2. This review focuses on the synthesis and functionalization of g-C3N4 and the recent advances of its application as a catalyst and a catalyst support in the electrocatalytic reduction of CO2. The modification of g-C3N4-based catalysts for enhanced CO2 reduction is critically reviewed. In addition, opportunities for future research on g-C3N4-based catalysts for electrocatalytic CO2 reduction are discussed. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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42 pages, 7875 KiB  
Review
Survey of Recent Advances in Molecular Fluorophores, Unconjugated Polymers, and Emerging Functional Materials Designed for Electrofluorochromic Use
by Ilies Seddiki, Brelotte Idriss N’Diaye and W. G. Skene
Molecules 2023, 28(7), 3225; https://doi.org/10.3390/molecules28073225 - 04 Apr 2023
Cited by 1 | Viewed by 1766
Abstract
In this review, recent advances that exploit the intrinsic emission of organic materials for reversibly modulating their intensity with applied potential are surveyed. Key design strategies that have been adopted during the past five years for developing such electrofluorochromic materials are presented, focusing [...] Read more.
In this review, recent advances that exploit the intrinsic emission of organic materials for reversibly modulating their intensity with applied potential are surveyed. Key design strategies that have been adopted during the past five years for developing such electrofluorochromic materials are presented, focusing on molecular fluorophores that are coupled with redox-active moieties, intrinsically electroactive molecular fluorophores, and unconjugated emissive organic polymers. The structural effects, main challenges, and strides toward addressing the limitations of emerging fluorescent materials that are electrochemically responsive are surveyed, along with how these can be adapted for their use in electrofluorochromic devices. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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35 pages, 7511 KiB  
Review
Pickering Emulsions Based in Inorganic Solid Particles: From Product Development to Food Applications
by Andreia Ribeiro, José Carlos B. Lopes, Madalena M. Dias and Maria Filomena Barreiro
Molecules 2023, 28(6), 2504; https://doi.org/10.3390/molecules28062504 - 09 Mar 2023
Cited by 6 | Viewed by 2667
Abstract
Pickering emulsions (PEs) have attracted attention in different fields, such as food, pharmaceuticals and cosmetics, mainly due to their good physical stability. PEs are a promising strategy to develop functional products since the particles’ oil and water phases can act as carriers of [...] Read more.
Pickering emulsions (PEs) have attracted attention in different fields, such as food, pharmaceuticals and cosmetics, mainly due to their good physical stability. PEs are a promising strategy to develop functional products since the particles’ oil and water phases can act as carriers of active compounds, providing multiple combinations potentiating synergistic effects. Moreover, they can answer the sustainable and green chemistry issues arising from using conventional emulsifier-based systems. In this context, this review focuses on the applicability of safe inorganic solid particles as emulsion stabilisers, discussing the main stabilisation mechanisms of oil–water interfaces. In particular, it provides evidence for hydroxyapatite (HAp) particles as Pickering stabilisers, discussing the latest advances. The main technologies used to produce PEs are also presented. From an industrial perspective, an effort was made to list new productive technologies at the laboratory scale and discuss their feasibility for scale-up. Finally, the advantages and potential applications of PEs in the food industry are also described. Overall, this review gathers recent developments in the formulation, production and properties of food-grade PEs based on safe inorganic solid particles. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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21 pages, 4731 KiB  
Review
Metal Oxide Gas Sensors to Study Acetone Detection Considering Their Potential in the Diagnosis of Diabetes: A Review
by Yasser H. Ochoa-Muñoz, Ruby Mejía de Gutiérrez and Jorge E. Rodríguez-Páez
Molecules 2023, 28(3), 1150; https://doi.org/10.3390/molecules28031150 - 24 Jan 2023
Cited by 5 | Viewed by 2426
Abstract
Metal oxide (MOx) gas sensors have attracted considerable attention from both scientific and practical standpoints. Due to their promising characteristics for detecting toxic gases and volatile organic compounds (VOCs) compared with conventional techniques, these devices are expected to play a key role in [...] Read more.
Metal oxide (MOx) gas sensors have attracted considerable attention from both scientific and practical standpoints. Due to their promising characteristics for detecting toxic gases and volatile organic compounds (VOCs) compared with conventional techniques, these devices are expected to play a key role in home and public security, environmental monitoring, chemical quality control, and medicine in the near future. VOCs (e.g., acetone) are blood-borne and found in exhaled human breath as a result of certain diseases or metabolic disorders. Their measurement is considered a promising tool for noninvasive medical diagnosis, for example in diabetic patients. The conventional method for the detection of acetone vapors as a potential biomarker is based on spectrometry. However, the development of MOx-type sensors has made them increasingly attractive from a medical point of view. The objectives of this review are to assess the state of the art of the main MOx-type sensors in the detection of acetone vapors to propose future perspectives and directions that should be carried out to implement this type of sensor in the field of medicine. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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18 pages, 3443 KiB  
Review
Stimulus-Responsive Ultrathin Films for Bioapplications: A Concise Review
by Maria Benelmekki and Jeong-Hwan Kim
Molecules 2023, 28(3), 1020; https://doi.org/10.3390/molecules28031020 - 19 Jan 2023
Cited by 1 | Viewed by 1715
Abstract
The term “nanosheets” has been coined recently to describe supported and free-standing “ultrathin film” materials, with thicknesses ranging from a single atomic layer to a few tens of nanometers. Owing to their physicochemical properties and their large surface area with abundant accessible active [...] Read more.
The term “nanosheets” has been coined recently to describe supported and free-standing “ultrathin film” materials, with thicknesses ranging from a single atomic layer to a few tens of nanometers. Owing to their physicochemical properties and their large surface area with abundant accessible active sites, nanosheets (NSHs) of inorganic materials such as Au, amorphous carbon, graphene, and boron nitride (BN) are considered ideal building blocks or scaffolds for a wide range of applications encompassing electronic and optical devices, membranes, drug delivery systems, and multimodal contrast agents, among others. A wide variety of synthetic methods are employed for the manufacturing of these NSHs, and they can be categorized into (1) top-down approaches involving exfoliation of layered materials, or (2) bottom-up approaches where crystal growth of nanocomposites takes place in a liquid or gas phase. Of note, polymer template liquid exfoliation (PTLE) methods are the most suitable as they lead to the fabrication of high-performance and stable hybrid NSHs and NSH composites with the appropriate quality, solubility, and properties. Moreover, PTLE methods allow for the production of stimulus-responsive NSHs, whose response is commonly driven by a favorable growth in the appropriate polymer chains onto one side of the NSHs, resulting in the ability of the NSHs to roll up to form nanoscrolls (NSCs), i.e., open tubular structures with tunable interlayer gaps between their walls. On the other hand, this review gives insight into the potential of the stimulus-responsive nanostructures for biosensing and controlled drug release systems, illustrating the last advances in the PTLE methods of synthesis of these nanostructures and their applications. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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18 pages, 3903 KiB  
Review
Advances in Thermoelectric Composites Consisting of Conductive Polymers and Fillers with Different Architectures
by Bingchen Huo and Cun-Yue Guo
Molecules 2022, 27(20), 6932; https://doi.org/10.3390/molecules27206932 - 16 Oct 2022
Cited by 6 | Viewed by 2102
Abstract
Stretchable wireless power is in increasingly high demand in fields such as smart devices, flexible robots, and electronic skins. Thermoelectric devices are able to convert heat into electricity due to the Seebeck effect, making them promising candidates for wearable electronics. Therefore, high-performance conductive [...] Read more.
Stretchable wireless power is in increasingly high demand in fields such as smart devices, flexible robots, and electronic skins. Thermoelectric devices are able to convert heat into electricity due to the Seebeck effect, making them promising candidates for wearable electronics. Therefore, high-performance conductive polymer-based composites are urgently required for flexible wearable thermoelectric devices for the utilization of low-grade thermal energy. In this review, mechanisms and optimization strategies for polymer-based thermoelectric composites containing fillers of different architectures will be introduced, and recent advances in the development of such thermoelectric composites containing 0- to 3-dimensional filler components will be presented and outlooked. Full article
(This article belongs to the Special Issue Feature Papers in Materials Chemistry)
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