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Nanomanufacturing, Volume 4, Issue 1 (March 2024) – 5 articles

Cover Story (view full-size image): Nanoporous anodic aluminum oxide (AAO) is a well-known porous nanomaterial template for electrical sensing. In resistive AAO humidity sensors, the signal intensity primarily depends on the thickness of AAO. Sensor response indicates the change in signal ratio from different relative humidity and is therefore positively correlated with the specific surface area. In terms of sensor differential sensitivity, the main structural factor is the total surface area. The performance of sensors is concerned with different nanostructures by adjusting process parameters. With the well-controlled profile of AAO, high-performance sensors will be able to be applied in our living environment and promote our quality of life. View this paper
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12 pages, 11718 KiB  
Article
UV Nanoimprint Lithography—Impact of Coating Techniques on Pattern Quality
by Johanna Rimböck, Patrick Schuster, Lisa Vsetecka and Christine Thanner
Nanomanufacturing 2024, 4(1), 69-80; https://doi.org/10.3390/nanomanufacturing4010005 - 14 Mar 2024
Viewed by 786
Abstract
In this work, three different coating techniques are compared and their applicability for ultraviolet nanoimprint lithography (UV-NIL) is investigated. As UV-NIL is considered a suitable volume manufacturing production solution for various emerging applications, it is mandatory to consider environmental aspects such as operational [...] Read more.
In this work, three different coating techniques are compared and their applicability for ultraviolet nanoimprint lithography (UV-NIL) is investigated. As UV-NIL is considered a suitable volume manufacturing production solution for various emerging applications, it is mandatory to consider environmental aspects such as operational energy use and material consumption as well as waste management. In this paper, spin coating, spray coating, and inkjet coating are used to coat both a high refractive index resin (n = 1.9) and a filler-free resin (n = 1.5), respectively. Variable Angle Spectroscopy Ellipsometry (VASE) was used to analyze the influence of different process parameters on the resin thickness as well as to compare the refractive index achieved from each coating technology. Finally, the applicability of the different coating methods for UV-NIL was investigated by imprinting the resin layers with different test structures. For the final imprints, the resolution, the surface roughness, and the pattern fidelity over 25 imprints was assessed using AFM. Finally, a comparison of the resin consumption and the process time was performed for each coating method. Full article
(This article belongs to the Special Issue Nanoimprinting and Sustainability)
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11 pages, 2060 KiB  
Article
Influence of Anodic Aluminum Oxide Nanostructures on Resistive Humidity Sensing
by Chin-An Ku, Chia-Wei Hung and Chen-Kuei Chung
Nanomanufacturing 2024, 4(1), 58-68; https://doi.org/10.3390/nanomanufacturing4010004 - 8 Mar 2024
Viewed by 580
Abstract
Humidity nanosensors play a vital role in modern technology industries, including weather forecasts, industrial manufacturing, agriculture, food and chemistry storage. In recent years, research on humidity sensors has focused on different materials such as ceramics, polymers, carbon-based materials, semiconductors, MXenes or triboelectric nanogenerators, [...] Read more.
Humidity nanosensors play a vital role in modern technology industries, including weather forecasts, industrial manufacturing, agriculture, food and chemistry storage. In recent years, research on humidity sensors has focused on different materials such as ceramics, polymers, carbon-based materials, semiconductors, MXenes or triboelectric nanogenerators, each with their own advantages and disadvantages. Among them, anodic aluminum oxide (AAO) is a well-known ceramic humidity sensor material with a long history of research and development. AAO humidity sensors offer advantages such as simple manufacturing processes, controllable nanostructures, high thermal stability and biocompatibility. However, traditional AAO fabrication still has disadvantages like high costs and longer process times. Hence, finding a low-cost and efficient method to fabricate AAO for controlling different nanostructures to meet the requirements is consistently a major research topic. From our previous studies, we have studied the relationship between the AAO capacitive humidity sensor and its nanostructures. In this paper, we explore the effect of an AAO nanoporous structure controlled by an anodization voltage of 20–40 V on the resistive-type humidity sensor performance instead of a capacitive one. We efficiently apply one-step hybrid pulse anodization at 25 °C to significantly reduce the processing time compared to the traditional two-step process under 0–10 °C. The AAO nanostructures and their impact on sensor measurements of humidity at 20–80 RH% will be discussed in detail. An electrical resistive sensing mechanism is established for further performance improvement by controlling anodization voltage. Full article
(This article belongs to the Special Issue Feature Papers for Nanomanufacturing in 2023)
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13 pages, 8345 KiB  
Article
Safe Explosion Works Promoted by 2D Graphene Structures Produced under the Condition of Self-Propagation High-Temperature Synthesis
by Alexander Petrovich Voznyakovskii, Mikhail Alekseevich Ilyushin, Aleksei Alexandrovich Vozniakovskii, Irina Vladimirovna Shugalei and Georgy Georgievich Savenkov
Nanomanufacturing 2024, 4(1), 45-57; https://doi.org/10.3390/nanomanufacturing4010003 - 8 Feb 2024
Viewed by 522
Abstract
The paper presents the results of a study on the effectiveness of few-layer graphene synthesized under SHS conditions from lignin as a modifying additive in creating composite pyrotechnic complexes based on porous silicon and calcium perchlorate. It was found that the addition of [...] Read more.
The paper presents the results of a study on the effectiveness of few-layer graphene synthesized under SHS conditions from lignin as a modifying additive in creating composite pyrotechnic complexes based on porous silicon and calcium perchlorate. It was found that the addition of few-layer graphene (20–30 wt. %) could significantly increase the probability of the ignition of pyrotechnic compositions by laser diode (infrared) radiation (wavelength of 976 nm and power of 15 MW/m2) compared to the initial pyrotechnic compositions. Using few-layer graphene also leads to a sharp increase in sensitivity to infrared laser radiation and the initiation of explosive transformations in retrofitted pyrotechnic compositions compared to the initial pyrotechnic compositions. Due to the high productivity and low cost of the technique for synthesizing few-layer graphene, the use of composite pyrotechnic compositions modified with few-layer graphene is profitable in the actual industry. A phenomenological model of the formation mechanism of 2D graphene structures under the conditions of the SHS process is proposed. Full article
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18 pages, 7375 KiB  
Article
Influence of γ-Irradiation on the Electronic Structure and the Chemical and Mechanical Properties of Poly(hydroxybutyrate-valerate)/Poly(caprolactone) Blends: Insights from Experimental Data and Computational Approaches
by Francisco Rosario, João Paulo Almirão de Jesus, Suzan Aline Casarin and Felipe de Almeida La Porta
Nanomanufacturing 2024, 4(1), 27-44; https://doi.org/10.3390/nanomanufacturing4010002 - 10 Jan 2024
Viewed by 1170
Abstract
In this study, we investigated the influence of γ-irradiation (0, 50, and 100 kGy) doses on the chemical and mechanical properties of biodegradable poly(hydroxybutyrate-valerate)/poly(caprolactone) (PHBV/PCL) polymer blends rich in low-molar-mass PCL, which were prepared using a co-rotating twin-screw extruder. In parallel, the density [...] Read more.
In this study, we investigated the influence of γ-irradiation (0, 50, and 100 kGy) doses on the chemical and mechanical properties of biodegradable poly(hydroxybutyrate-valerate)/poly(caprolactone) (PHBV/PCL) polymer blends rich in low-molar-mass PCL, which were prepared using a co-rotating twin-screw extruder. In parallel, the density functional theory (DFT) and the time-dependent DFT (TD-DFT) methods were used together with a model containing four monomer units to provide an insight into the electronic structure, chemical bonds, and spectroscopic (such as Nuclear Magnetic Resonance (NMR) and Ultraviolet-visible (UV-vis)) properties of PHBV and PCL blend phases, which are critical for predicting and designing new materials with desired properties. We found that an increase in γ-irradiation doses caused splitting instead of crosslinks in the polymer chains, which led to evident deformation and an increase in tensile strength at break of 2.0 to 5.7 MPa for the PHBV/PCL blend. Further, this led to a decrease in crystallinity and proved the occurrence of a more favorable interaction between the blend phases. Full article
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26 pages, 3681 KiB  
Article
New Polymers In Silico Generation and Properties Prediction
by Andrey A. Knizhnik, Pavel V. Komarov, Boris V. Potapkin, Denis B. Shirabaykin, Alexander S. Sinitsa and Sergey V. Trepalin
Nanomanufacturing 2024, 4(1), 1-26; https://doi.org/10.3390/nanomanufacturing4010001 - 19 Dec 2023
Viewed by 752
Abstract
We present a theoretical approach for the in silico generation of new polymer structures for the systematic search for new materials with advanced properties. It is based on Bicerano’s Regression Model (RM), which uses the structure of the smallest repeating unit (SRU) for [...] Read more.
We present a theoretical approach for the in silico generation of new polymer structures for the systematic search for new materials with advanced properties. It is based on Bicerano’s Regression Model (RM), which uses the structure of the smallest repeating unit (SRU) for fast and adequate prediction of polymer properties. We have developed the programs (a) GenStruc, for generating the new polymer SRUs using the enumeration and Monte Carlo algorithms, and (b) PolyPred, for predicting properties for a given input polymer as well as for multiple structures stored in the database files. The structure database from the original Bicerano publication is used to create databases of backbones and pendant groups. A database of 5,142,153 unique SRUs is generated using the scaffold-based combinatorial method. We show that using only known backbones of the polymer SRU and varying the pendant groups can significantly improve the predicted extreme values of polymer properties. Analysis of the obtained results for the dielectric constant and refractive index shows that the values of the dielectric constant are higher for polyhydrazides than for polyhydroxylamines. The high value predicted for the refractive index of polythiophene and its derivatives is in agreement with the experimental data. Full article
(This article belongs to the Special Issue Nanomanufacturing Empowered with Artificial Intelligence)
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