Hybrid silica aerogels from bridged silicon alkoxides: ultralow thermal conductivity for low-temperature applications

IF 2.3 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS

Journal of Sol-Gel Science and Technology Pub Date : 2025-03-17 DOI:10.1007/s10971-025-06724-6

A. M. Abebe, M. Biesuz, C. Vakifahmetoglu, M. Cassetta, G. D. Sorarù

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引用次数: 0

Abstract

Hybrid silica aerogels are promising materials for thermal insulation applications. Highly porous aerogels were synthesized from bridged bis(triethoxysilyl)methane BTEM and triethoxysilane TREOS silicon alkoxides via the sol‒gel process. The carbon content in the hybrid aerogels decreased with increasing amounts of TREOS. Crack-free monolith aerogels were synthesized through supercritical drying, which is crucial for thermal and optical investigations. The aerogels are characterized by high BET surface areas ranging from 700 to 1400 m²/g, pore volumes between 2.0 and 10.5 cm³/g, and a maximum porosity of 95%. The thermal conductivity of the aerogels at room temperature was measured via a hot disk apparatus. The materials exhibited ultralow thermal conductivity, reaching a minimum value of 15 mW/mK. This value ranks among the lowest reported values for silica-based aerogels in the literature. Optical transmittance measurements indicated high transparency, exceeding 80% in the visible region. Therefore, these exceptional properties of low density, high optical transparency, and low thermal conductivity make these materials promising candidates for transparent insulation applications.

Graphical Abstract

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由桥接硅烷氧化物制成的杂化硅气凝胶：低温应用的超低导热性

杂化二氧化硅气凝胶是一种很有前途的保温材料。以双（三乙氧基硅烷）甲烷BTEM和三乙氧基硅烷TREOS硅烷氧化物为原料，采用溶胶-凝胶法制备了多孔气凝胶。杂化气凝胶中的碳含量随着TREOS用量的增加而降低。采用超临界干燥法制备了无裂纹整体气凝胶，对热、光学研究具有重要意义。该气凝胶的BET比表面积在700 ~ 1400 m²/g之间，孔隙体积在2.0 ~ 10.5 cm³/g之间，最大孔隙率为95%。通过热盘仪测量了气凝胶在室温下的导热系数。材料的导热系数极低，最小值为15 mW/mK。该值是文献中硅基气凝胶的最低报告值之一。光学透射率测量表明高透明度，在可见光区域超过80%。因此，这些低密度、高光学透明度和低导热性的特殊性能使这些材料成为透明绝缘应用的有希望的候选者。图形抽象

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来源期刊

Journal of Sol-Gel Science and Technology 工程技术-材料科学：硅酸盐

CiteScore

4.70

自引率

4.00%

发文量

280

审稿时长

2.1 months

期刊介绍： The primary objective of the Journal of Sol-Gel Science and Technology (JSST), the official journal of the International Sol-Gel Society, is to provide an international forum for the dissemination of scientific, technological, and general knowledge about materials processed by chemical nanotechnologies known as the "sol-gel" process. The materials of interest include gels, gel-derived glasses, ceramics in form of nano- and micro-powders, bulk, fibres, thin films and coatings as well as more recent materials such as hybrid organic-inorganic materials and composites. Such materials exhibit a wide range of optical, electronic, magnetic, chemical, environmental, and biomedical properties and functionalities. Methods for producing sol-gel-derived materials and the industrial uses of these materials are also of great interest.