Association of Titania with Nonionic Block Copolymers in Ethanol: The Early Stages of Templating and Film Formation
Association of Titania with Nonionic Block Copolymers in Ethanol: The Early Stages of Templating and Film Formation
复制标题
二氧化钛与乙醇中非离子嵌段共聚物的缔合：模板化和成膜的早期阶段
DOI：
10.1021/cm100511z
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发表时间：
2010
影响因子：
8.6
通讯作者：
Edler K
中科院分区：
文献类型：
--
作者：
Edler K
我们通过在乙醇溶液表面的自发生长制备了自支撑、独立的钛表面活性剂介观结构薄膜，作为蒸发诱导自组装的替代合成途径。用小角中子散射和布鲁斯特角显微镜观察了表面活性剂在二氧化钛酒精溶液中模板化和界面膜形成的初始阶段。包括二氧化钛前驱体浓度、酸浓度和表面活性剂浓度在内的参数变化允许探测形成时间和途径。这些时间分辨的二氧化钛发育观察代表了形成研究中的一项新成就，并允许提出二氧化钛-表面活性剂薄膜的形成机制。溶液中的胶束经历最初缓慢的二氧化钛积累，随后快速生长出二氧化钛外壳，随后又经历一个缓慢的生长期，这些物质在溶液界面积聚，通过溶液表面蒸发驱动的相变形成薄膜。这种机制在早期发育阶段没有溶液聚集，这对于理解早期溶液阶段的发展、开发基于蒸发诱导自组装过程的新材料以及界面膜的自发生长具有重要意义。
We have prepared self-supporting, free-standing titania-surfactant mesostructured films via spontaneous growth on the surface of ethanolic solutions, as an alternative synthetic route to evaporation induced self-assembly. The initial stages of surfactant templating and interfacial film formation in alcoholic solutions of titania with a polyethylene−poly(ethylene glycol) surfactant have been observed by small angle neutron scattering and Brewster angle microscopy. Variation of parameters including the titania precursor concentration, acid concentration, and surfactant concentration allowed formation times and pathways to be probed. These time-resolved observations of titania development represent a novel achievement in formation studies and have allowed a formation mechanism for titania−surfactant films to be proposed. Micelles in solution undergo an initial slow accumulation of titania, followed by rapid growth of a titania shell, followed again by a slow growth period, and these species accumulate at the solution interface to form the film via a phase transition driven by evaporation from the solution surface. This mechanism shows no solution aggregation in early developmental stages and is significant in understanding early solution phase development and for developing new materials based on evaporation induced self-assembly processes as well as for spontaneous growth of films at interfaces.