天然纤维素物质模板制备功能纳米材料研究进展

Functional nanostructured materials templated by natural cellulose substance

自然生物物质特殊的天然结构赋予其人工材料所难以比拟的优异功能,是构建人造功能纳米结构材料理想的模板物质.天然纤维素物质作为一种常见的天然高分子化合物,从宏观到分子层次的独特阶层结构及其在纳米层级上的多孔网状形貌可期赋予以其为模板而制备的有关人造材料独特的性质和功能.以纳米层级的精度和客体基质(无机和有机的)精确复制自然纤维素物质,能够最大限度地把其优异性能(如多孔隙结构和高内表面积)引入到相应的人造材料中去.应用表面溶胶-凝胶方法可以在纤维素物质的纳米纤维表面以纳米级别的厚度可控沉积金属氧化物凝胶薄膜,特定功能的客体物质能够进一步地表面组装于其上;继之以合适的方法去除纤维素模板成分即得到相应的具有纤维素物质阶层状结构和形貌的人造功能材料.本文简述了以此为基础设计和构建新型纳米结构材料(如金属氧化物及其复合纳米材料、聚合物纳米材料、硅和金属纳米材料等)的研究进展.以自然纤维素物质为模板或支架开发功能材料是一条获得新型功能纳米材料的简便、低成本和对环境友好的捷径.

Natural bio-substances are ideal template substrates for the fabrication of functional artificial nanostructured materials due to their unique naturally produced structures and properties that prior to man-made ones. As being one of the most abundant natural polymers, natural cellulose substances possess unique structural hierarchies from macro-to molecular scales, as well as porous network structures at nanometer levels; hence excellent properties and functionalities are expected for the artificial matters templated by which. To introduce the unique structural features and properties such as the porous structures and the high inner surface areas of the natural cellulose substances into artificial functional materials to the maximum extent possible, duplication of natural cellulose substances by using various inorganic and organic guest substances with nanometer precisions provides an efficient solution. Ultrathin metal oxide gel films with nanometer thicknesses can be deposited onto the nanofibers of bulk cellulose substances by means of the surface sol-gel process, and specific guest substrates can be further assembled onto the film surfaces; further removal of the cellulose components by proper treatment results in artificial functional nanostructured materials possessing the hierarchical structures and morphologies of the initial cellulose substances. In this review, the recent research progress in this aspect is summarized, showing the results on the design and fabrication of novel nanomaterials such as nanostructured metal oxides and their composites, polymeric nanomaterials as well as silicon and metal nanomaterials. It has been demonstrated that it is a facile, low-coat and environment friendly shortcut to functional materials by using natural cellulose substances as templates or scaffolds.