SGER: Polarization Near-Field Scanning Optical Microscopy of Ordered Polymers

传统光学显微镜的分辨率受“远场”衍射的限制，是由所使用的电磁辐射的波长决定的。最近的研究已经成功地证明，一个基于拉伸光纤的显微镜，在非常接近标本（在“近场”）的范围内工作，受探针尺寸（约20纳米）的限制，而不受考虑因素的限制。在这项工作中，我们将开展一个探索性项目，开发并应用偏振近场扫描光学显微镜（PNSOM）作为一种新的表征技术，来确定各种有序聚合物材料中局部分子组织的空间分布（通过双折射）。几个系统将作为该计划的初步研究目标。液晶/聚合物乳液中的局部双折射（用于光电应用）将提供有关晶体/聚合物界面上分子组织的信息。热致性和溶致性聚合物的原位研究将允许在中间相形成和伴随热处理的重组之前确定局部超分子组织。虽然这些系统将是我们初步研究的重点，但我们预计PNSOM作为一种高分辨率成像技术，有望在涉及结晶、表面取向、局部应力和相相容的研究中被证明是有益的。该技术是非破坏性的，不需要资金、维护和高真空，这是几种高分辨率成像技术所需要的。＊＊＊

9315676 Spontak The resolution of a conventional optical microscope, limited by diffraction in the "far-field," is dictated by the wavelength of the electromagnetic radiation employed. Recent studies have successfully demonstrated that a microscope based on a drawn optical fiber and operated within very close proximity to a specimen (in the "near-field") is limited by the size of the probe (to ca. 20 nm) and not by considerations. In this work, we will carry out an exploratory program in which polarization near-field scanning optical microscopy (PNSOM) is developed and applied as a novel characterization technique to determine the spatial distribution of local molecular organization (through birefringence) in a variety of ordered polymeric materials. Several systems will be targeted for initial studies in this program. Local birefringence in a liquid crystal/polymer emulsion (for electro-optical applications) would provide information regarding molecular organization at the crystal/polymer interface. In-situ studies of thermotropic and lyotropic polymers will permit determination of local supramolecular organization preceding mesophase formation and reorganization accompanying thermal treatment. While these systems will be the focus of our initial studies, we foresee PNSOM as a high-resolution imaging technique promising to prove beneficial in studies involving crystallization, surface orientation, localized stress, and phase compatibilization. This technique is non-destructive and does not require the capital, maintenance, and high-vacuum needed by several high-resolution imaging techniques. ***