Dynamics of Phase Separating Thin Film Blends

9974366复合材料本研究将集中于相分离薄膜共混物的动力学研究。这些研究旨在通过测量空气/聚合物和聚合物/衬底界面的润湿层生长，紧挨着润湿层的相形态，区域粗化，表面粗糙度以及湿相和非湿相之间的粗糙度来全面了解薄膜动力学。为了探索潜在的原理，动力学将被研究为材料参数的函数，包括分子量和组成，过程依赖变量包括薄膜厚度和温度，以及衬底表面能。为了测试其普遍行为，将研究一系列模型共混体系，包括具有较低临界溶液温度和较高临界溶液温度的共混体系，以及共聚物共混体系。为了直接测试相分离和润湿之间的相互作用，将使用AFM直接成像润湿相选择性蚀刻后的近表面形貌。将使用低能、前反冲光谱、LE-FRES和中子反射率跟踪湿层的生长。此外，LE-FRES将用于横向非均匀样品的分析。为了量化横向相组成和可能的曲面界面宽度，分析TEM将在内部开发，近边缘x射线吸附精细结构光谱将与NIST合作进行。除了均匀的衬底外，研究的目标是控制横向剖面研究，润湿特性将使用接触角测角仪和AFM进行测量。所提出的研究的一个重要组成部分是将模型系统的基础研究扩展到包括离子结合促进剂和图图化介电材料在内的先进材料。关于聚合物薄膜和涂层的拟议研究将提供基本的科学理解，可能影响健康（例如隐形眼镜，膜）和微电子（例如介电和电阻）领域的先进技术应用。本科生（4人/年）将在夏季与公立高中教师一起继续参与研究项目。

9974366CompostoThe proposed research will focus on the dynamics of phase separating thin film blends. These studies aim to develop a comprehensive understanding of thin film kinetics by measuring the wetting layer growth at both the air / polymer and polymer / substrate interfaces, phase morphology immediately beneath the wetting layer, domain coarsening, surface roughness, and the roughness between the wet and non-wet phases. To probe underlying principles, dynamics will be studied as a function of materials parameters including molecular weight and composition, process dependent variables including film thickness and temperature, and substrate surface energy. To test for universal behavior, a range of model blend systems will be investigated including blends with a lower critical solution temperature and an upper critical solution temperature, in addition to copolymer blends. To directly test the interplay between phase separation and wetting, AFM will be used to directly image the near-surface morphology after selective etching of the wetting phase. Wetting layer growth will be followed using low-energy, forward recoil spectrometry, LE-FRES, and neutron reflectivity. Furthermore, LE-FRES will be developed for the analysis of laterally non-uniform samples. To quantify lateral phase composition and possibly the interfacial width at curved interfaces, analytical TEM will be developed in-house and near edge x-ray adsorption fine structure spectroscopy will be performed in collaboration with NIST. In addition to homogeneous substrates, studies will aim to control lateral profiling studies, wetting properties will be measured using a contact angle goniometer and AFM. An important component of the proposed research is to extend fundamental studies on model systems to advanced materials involving ionomer adhesion promoters and patterned dielectric materials.The proposed research on polymer films and coatings will provide fundamental scientific understanding that could impact advanced technological applications in the health (e.g. contact lenses, membranes) and microelectronics (e.g. dielectrics and resists) fields. Undergraduates (4/year) will continue to participate in the research program, along with public high-school teachers during the summer.