Baumgärtner Benjamin, Möller Hendrik, Neumann Thomas, Volkmer Dirk
Chair of Solid State and Materials Chemistry, University of Augsburg, 86159 Augsburg, Germany.
Schwenk Zement KG, Ulm 89077, Germany.
Beilstein J Nanotechnol. 2017 May 26;8:1145-1155. doi: 10.3762/bjnano.8.116. eCollection 2017.
A facile method to coat carbon fibers with a silica shell is presented in this work. By immobilizing linear polyamines on the carbon fiber surface, the high catalytic activity of polyamines in the sol-gel-processing of silica precursors is used to deposit a silica coating directly on the fiber's surface. The surface localization of the catalyst is achieved either by attaching short-chain polyamines (e.g., tetraethylenepentamine) via covalent bonds to the carbon fiber surface or by depositing long-chain polyamines (e.g., linear poly(ethylenimine)) on the carbon fiber by weak non-covalent bonding. The long-chain polyamine self-assembles onto the carbon fiber substrate in the form of nanoscopic crystallites, which serve as a template for the subsequent silica deposition. The silicification at close to neutral pH is spatially restricted to the localized polyamine and consequently to the fiber surface. In case of the linear poly(ethylenimine), silica shells of several micrometers in thickness can be obtained and their morphology is easily controlled by a considerable number of synthesis parameters. A unique feature is the hierarchical biomimetic structure of the silica coating which surrounds the embedded carbon fiber by fibrillar and interconnected silica fine-structures. The high surface area of the nanostructured composite fiber may be exploited for catalytic applications and adsorption purposes.
本文介绍了一种在碳纤维表面包覆二氧化硅壳层的简便方法。通过将线性多胺固定在碳纤维表面，利用多胺在二氧化硅前驱体溶胶 - 凝胶过程中的高催化活性，直接在纤维表面沉积二氧化硅涂层。催化剂的表面定位可通过将短链多胺（如四乙烯五胺）通过共价键连接到碳纤维表面，或通过弱非共价键将长链多胺（如线性聚（乙烯亚胺））沉积在碳纤维上来实现。长链多胺以纳米微晶的形式自组装到碳纤维基材上，作为后续二氧化硅沉积的模板。接近中性pH值的硅化反应在空间上局限于局部多胺，进而局限于纤维表面。对于线性聚（乙烯亚胺），可以获得厚度达几微米的二氧化硅壳层，其形态可通过大量合成参数轻松控制。一个独特的特点是二氧化硅涂层的分级仿生结构，它通过纤维状且相互连接的二氧化硅精细结构围绕着嵌入的碳纤维。纳米结构复合纤维的高比表面积可用于催化应用和吸附目的。
