Epitaxial growth of a surfactant-silica mesostructure on oriented polyimide films
Epitaxial growth of a surfactant-silica mesostructure on oriented polyimide films
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表面活性剂-二氧化硅介观结构在取向聚酰亚胺薄膜上的外延生长
DOI：
10.1016/j.micromeso.2006.12.023
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发表时间：
2007
影响因子：
5.2
通讯作者：
H. Miyata
中科院分区：
文献类型：
--
作者：
H. Miyata
在本文中，我回顾了我们过去的工作，在介孔二氧化硅薄膜中的介孔的面内排列的宏观控制。介孔结构的二氧化硅外延生长在聚酰亚胺涂层与表面各向异性，以提供二氧化硅膜与完全控制的介孔结构在整个基板表面。通过各向同性聚酰亚胺涂层的机械摩擦后处理以及通过前体聚酰胺酸的Langmuir-Blodgett（LB）膜的热酰亚胺化形成各向异性聚酰亚胺涂层。聚酰亚胺底层的化学各向异性被证明是更重要的外延生长比形态各向异性。在各向异性聚酰亚胺上不仅形成单轴取向的二维（2D）六方介观结构，而且形成其中球形介孔的面内排列完全受控的单晶三维（3D）六方介观结构。外延生长通过在各向异性聚合物表面上的介观结构的二氧化硅种子的非均质成核和生长进行水热。据认为，各向异性聚合物链和表面活性剂的烷基链之间的疏水相互作用引起所观察到的外延生长。它示出，在传统的晶体外延生长的对比，所观察到的二氧化硅介观结构的外延生长不需要与下面的聚酰亚胺的化学结构的分子尺度的尺寸匹配。
In this paper, I review our past works on macroscopic control of in-plane arrangement of mesopores in mesoporous silica films. Mesostructured silicas are grown epitaxially on polyimide coatings with surface anisotropy to provide silica films with fully controlled mesoporous structures over the whole of the substrate surface. The anisotropic polyimide coatings are formed by a mechanical rubbing post-treatment of isotropic polyimide coatings as well as by thermal imidation of a Langmuir–Blodgett (LB) film of the precursor polyamic acid. The chemical anisotropy of the polyimide underlayer is shown to be more important for the epitaxial growth than the morphological anisotropy. Not only the uniaxially aligned two-dimensional (2D) hexagonal mesostructure but also the single-crystalline three-dimensional (3D) hexagonal mesostructure, in which the in-plane arrangement of the spherical mesopores is entirely controlled, are formed on the anisotropic polyimide. The epitaxial growth takes place hydrothermally through heterogeneous nucleation and growth of mesostructured silica seeds on the anisotropic polymer surfaces. It is considered that the hydrophobic interactions between the anisotropic polymer chains and the alkyl chains of the surfactants cause the observed epitaxial growth. It is shown that, in contrast to the conventional epitaxial growth of crystals, the observed epitaxial growth of silica mesostructures does not require molecular-scaled size matching with the chemical structure of the underlying polyimide.