Journal of Colloid and Interface Science ( IF 9.4 ) Pub Date : 2021-09-24 , DOI: 10.1016/j.jcis.2021.09.128 Maryam Fashandi 1 , Solmaz Karamikamkar 1 , Siu N Leung 2 , Hani E Naguib 3 , Jiang Hong 4 , Bingqing Liang 4 , Chul B Park 1
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Hypothesis
Alkyltrimethoxysilane (ATMS) is among most widely used silane coupling agents. These commercially available, reasonably priced chemicals are often utilized to improve the compatibility of inorganic surfaces with organic coatings. With three hydrolysable moieties, ATMS is an outstanding candidate for solving the hydrophilicity, moisture sensitivity and high cost of silica aerogels. However, ATMS has a non-hydrolysable alkyl chain that undergoes cyclization reactions. The alkyl chain prevents ATMS from being incorporated in aerogel structures.
Polyvinyltrimethoxysilane (PVTMS) is a silica precursor that offers two types of crosslinking to the final aerogel product. This strong doubly-crosslinked network can potentially suppress the cyclization reactions of ATMS and include it in aerogel structure.
Experiments
PVTMS was used with ATMS having different alkyl lengths (3–16 carbons) and loadings (25 or 50 wt%) as the silica precursors. Acid and base catalysts were used to perform hydrolysis and condensation reactions on the mixture and ATMS:PVTMS aerogels were obtained via supercritical drying.
Findings
The incorporation of ATMS in the aerogels was approved by different characterization methods. Results showed that ATMS:PVTMS aerogels possess hydrophobicity (θ ∼ 130°), moisture resistance, varying surface area (44–916 m2·g−1), meso/microporous structure and thermal insulation properties (λ ∼ 0.03 W·m-1K−1). These samples also showed excellent performance in oil and organic solvent adsorption.
中文翻译：
不同烷基链长疏水性烷基三甲氧基硅烷-聚乙烯基三甲氧基硅烷杂化气凝胶的合成、结构和性能
假设
烷基三甲氧基硅烷 (ATMS) 是应用最广泛的硅烷偶联剂之一。这些市售的、价格合理的化学品通常用于提高无机表面与有机涂层的相容性。ATMS 具有三个可水解部分，是解决二氧化硅气凝胶亲水性、湿度敏感性和高成本的杰出候选者。然而，ATMS 有一个不可水解的烷基链，会发生环化反应。烷基链可防止 ATMS 掺入气凝胶结构中。
聚乙烯基三甲氧基硅烷 (PVTMS) 是一种二氧化硅前体，可为最终气凝胶产品提供两种类型的交联。这种强大的双交联网络可以潜在地抑制 ATMS 的环化反应并将其包含在气凝胶结构中。
实验
PVTMS 与具有不同烷基长度（3-16 个碳）和负载（25 或 50 重量％）的 ATMS 一起用作二氧化硅前体。使用酸和碱催化剂对混合物进行水解和缩合反应，并通过超临界干燥获得 ATMS:PVTMS 气凝胶。
发现
ATMS 在气凝胶中的加入得到了不同的表征方法的批准。结果表明，ATMS:PVTMS 气凝胶具有疏水性（θ ∼ 130°）、防潮性、可变表面积（44–916 m 2 ·g -1）、介孔/微孔结构和隔热性能（λ ∼ 0.03 W·m - 1 K -1 )。这些样品在油和有机溶剂吸附方面也表现出优异的性能。
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