Focused Ion Beam Lift Out Cross Sectional Transmission Electron Microscopy of Polymer Nanostructured Films Ordered on Attractive Surfaces

在相互作用表面附近的双组分聚合物体系，如均聚物共混物或嵌段共聚物熔体，本质上是非均质体系。组分和底物之间的化学亲和力的差异导致了系统中的择优取向。在大多数这种性质的研究中，硅一直是选择的衬底，因为它可以以单晶的形式获得，表面原子光滑。此外，它在半导体工业中被广泛使用，在那里已经开发了许多程序来改变表面能量并应用化学和地形图案。目前已知的关于聚合物表面取向的大部分信息是通过中子和X射线反射率法或动态二次离子质谱仪获得的。当方向垂直于曲面且在平行于曲面的平面中对称时，这些方法效果最佳。对于横截面样品，在原子光滑的硅上有序的聚合物薄膜的透射电子显微镜研究一直是非常困难的。用超微切割法直接切割HARD硅晶体是不可能的，离子研磨是一个漫长而乏味的过程，结果不确定。%该奖项由NSF 94-147“少数民族研究规划拨款”提供初始资金，用于在纽约州立大学石溪分校建立聚合物纳米结构电子显微镜计划，并研究在有吸引力的表面上有序的均聚物共混物的增容作用。在这项初步研究中将解决以下问题：(A)聚焦离子束提拉程序能否用于在硅上制备新的有序薄膜的横截面？(B)独一无二的定制聚合物纳米结构能否在均聚物共混物中诱导相容？

A two component polymer system, such as a homopolymer blend or a block copolymer melt, in the vicinity of an interactive surface is an inherently inhomogeneous system. The difference in chemical affinity between the components and the substrate induces a preferred orientation in the system. In most studies of this nature, silicon has been the substrate of choice since it can be obtained in single crystal form with an atomically smooth surface. Furthermore, it is used extensively in the semiconductor industry where numerous procedures have been developed to modify the surface energy and apply both chemical and topographical patterns. Most of what is known today on the orientation of polymers at surfaces has been obtained by neutron and x-ray reflectivity methods or dynamic secondary ion mass spectrometry. These methods work best when the orientation occurs normal to the surface and is symmetric in the plane parallel to the surface. Transmission electron microscopy studies of thin polymer films ordered on atomically smooth silicon have been very difficult for cross-sectional specimens. It was not possible to directly section heard silicon crystals by ultramicrotomy and ion milling is a long and tedious process with uncertain results.%%%This award under NSF 94-147 "Minority Research Planning Grant" provides initial funding to establish a polymer nanostructured electron-microscopy program at SUNY Stony Brook and to investigate compatibilization of homopolymer blends ordered on attractive surfaces. The following issues will be addressed in this initial study: (a) Can the focused ion-beam lift-out procedure be used to produce cross sections of novel thin films ordered on silicon? (b) Can uniquely tailored polymer nanostructures induce miscibility in hompolymer blends?