Nanomaterials in Aerogel Composites

A special issue of Nanomaterials (ISSN 2079-4991). This special issue belongs to the section "Nanocomposite Materials".

Deadline for manuscript submissions: 20 June 2024 | Viewed by 4610

Special Issue Editors

School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
Interests: aerogel-related nanoporous materials; interaction between aerogels and other matter; superblack materials; bio-inspired materials; sonic materials with ultralow sound speed
School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
Interests: preparation, microfabrication, and engineering application of aerogels
Dr. Jialu Lu
E-Mail Website
Guest Editor
School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
Interests: preparation of aerogels and the application of superblack materials
Dr. Lidija Şiller
E-Mail Website
Guest Editor
School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
Interests: nanoscale science and nanotechnology; CO2 capture and storage; aerogel materials; thermoelectrics; supercapacitors; nanotoxicology physics and chemistry at solid surfaces; optical, electronic and structural properties of nanoscale materials; electron and photon stimulated desorption in ices

Special Issue Information

Dear Colleagues,

As a functional highly porous nanomaterial, aerogels exhibit a suitable appearance, delicate hierarchical structure, and unique properties. It is amazing that these marvelous materials possess ultralow thermal conductivity, ultralow dielectric constant (or even negative permittivity and permeability), ultralow refractive index (or ultralow reflectance), ultralow sound speed, low diffusion coefficient, and many other characteristics, only derived from a slender and fragile microstructure with ultralow solid proportion.

In this Special Issue, we plan to focus on the topic of nanoporous aerogel composites, which combine the properties of different components to address the shortcomings of aerogels (such as brittleness) and develop applications in special fields. In addition, it is worth noting that some fundamental issues have not been well resolved so far, including the interactions between aerogels and other matter, synergistic effect among different components, long-term evaluation, and so on. Thus, we warmly welcome contributions relevant to the fundamental mechanism, unique preparation method, efficient posttreatment method, significant property, advanced functional application, and long-term estimation of aerogel-related composites. We hope this issue will provide an open and interdisciplinary platform for researchers from aerogel science and engineering.

Dr. Ai Du
Prof. Dr. Bin Zhou
Dr. Jialu Lu
Dr. Lidija Şiller
Guest Editors

Manuscript Submission Information

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Keywords

  • aerogels
  • nanoporous
  • composites
  • interaction
  • properties
  • hierarchical structure
  • subwavelength structure
  • advanced application

Published Papers (3 papers)

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Research

16 pages, 6012 KiB  
Article
Study of Electrical and Dielectric Behaviors of Copper-Doped Zinc Oxide Ceramic Prepared by Spark Plasma Sintering for Electronic Device Applications
Nanomaterials 2024, 14(5), 402; https://doi.org/10.3390/nano14050402 - 22 Feb 2024
Viewed by 362
Abstract
In this study, Cu-doped ZnO aerogel nanoparticles with a 4% copper concentration (Cu4ZO) were synthesized using a sol–gel method, followed by supercritical drying and heat treatment. The subsequent fabrication of Cu4ZO ceramics through Spark Plasma Sintering (SPS) was characterized by X-ray diffraction (XRD), [...] Read more.
In this study, Cu-doped ZnO aerogel nanoparticles with a 4% copper concentration (Cu4ZO) were synthesized using a sol–gel method, followed by supercritical drying and heat treatment. The subsequent fabrication of Cu4ZO ceramics through Spark Plasma Sintering (SPS) was characterized by X-ray diffraction (XRD), field-emission gun scanning electron microscopy (FE-SEM) equipped with EDS, and impedance spectroscopy (IS) across a frequency range of 100 Hz to 1 MHz and temperatures from 270 K to 370 K. The SPS–Cu4ZO sample exhibited a hexagonal wurtzite structure with an average crystallite size of approximately 229 ± 10 nm, showcasing a compact structure with discernible pores. The EDS spectrum indicates the presence of the base elements zinc and oxygen with copper like the dopant element. Remarkably, the material displayed distinct electrical properties, featuring high activation energy values of about 0.269 ± 0.021 eV. Complex impedance spectroscopy revealed the impact of temperature on electrical relaxation phenomena, with the Nyquist plot indicating semicircular arc patterns associated with grain boundaries. As temperature increased, a noticeable reduction in the radius of these arcs occurred, coupled with a shift in their center points toward the axis center, suggesting a non-Debye-type relaxation mechanism. Dielectric analyses revealed a temperature-driven evolution of losses, emphasizing the material’s conductivity impact. Non-Debye-type behavior, linked to ion diffusion, sheds light on charge storage dynamics. These insights advance potential applications in electronic devices and energy storage. Full article
(This article belongs to the Special Issue Nanomaterials in Aerogel Composites)
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11 pages, 4532 KiB  
Article
Cost-Effective Preparation of Hydrophobic and Thermal-Insulating Silica Aerogels
Nanomaterials 2024, 14(1), 119; https://doi.org/10.3390/nano14010119 - 03 Jan 2024
Viewed by 771
Abstract
The aim of this study is to reduce the manufacturing cost of a hydrophobic and heat-insulating silica aerogel and promote its industrial application in the field of thermal insulation. Silica aerogels with hydrophobicity and thermal-insulation capabilities were synthesized by using water-glass as the [...] Read more.
The aim of this study is to reduce the manufacturing cost of a hydrophobic and heat-insulating silica aerogel and promote its industrial application in the field of thermal insulation. Silica aerogels with hydrophobicity and thermal-insulation capabilities were synthesized by using water-glass as the silicon source and supercritical drying. The effectiveness of acid and alkali catalysis is compared in the formation of the sol. The introduction of sodium methyl silicate for the copolymerization enhances the hydrophobicity of the aerogel. The resultant silica aerogel has high hydrophobicity and a mesoporous structure with a pore volume exceeding 4.0 cm3·g−1 and a specific surface area exceeding 950 m2·g−1. The obtained silica aerogel/fiber-glass-mat composite has high thermal insulation, with a thermal conductivity of less than 0.020 W·m−1·K−1. The cost-effective process is promising for applications in the industrial preparation of silica aerogel thermal-insulating material. Full article
(This article belongs to the Special Issue Nanomaterials in Aerogel Composites)
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11 pages, 2771 KiB  
Article
Passive Daytime Radiative Cooling of Silica Aerogels
Nanomaterials 2023, 13(3), 467; https://doi.org/10.3390/nano13030467 - 24 Jan 2023
Cited by 7 | Viewed by 2874
Abstract
Silica aerogels are one of the most widely used aerogels, exhibiting excellent thermal insulation performance and ultralow density. However, owing to their plenitude of Si-O-Si bonds, they possess high infrared emissivity in the range of 8–13 µm and are potentially robust passive radiative [...] Read more.
Silica aerogels are one of the most widely used aerogels, exhibiting excellent thermal insulation performance and ultralow density. However, owing to their plenitude of Si-O-Si bonds, they possess high infrared emissivity in the range of 8–13 µm and are potentially robust passive radiative cooling (PRC) materials. In this study, the PRC behavior of traditional silica aerogels prepared from methyltrimethoxysilane (MTMS) and dimethyldimethoxysilane (DMDMS) in outdoor environments was investigated. The silica aerogels possessed low thermal conductivity of 0.035 W/m·K and showed excellent thermal insulation performance in room environments. However, sub-ambient cooling of 12 °C was observed on a clear night and sub-ambient cooling of up to 7.5 °C was achieved in the daytime, which indicated that in these cases the silica aerogel became a robust cooling material rather than a thermal insulator owing to its high IR emissivity of 0.932 and high solar reflectance of 0.924. In summary, this study shows the PRC performance of silica aerogels, and the findings guide the utilization of silica aerogels by considering their application environments for achieving optimal thermal management behavior. Full article
(This article belongs to the Special Issue Nanomaterials in Aerogel Composites)
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