Vapor Deposition Polymerization of Porous Polymers

CBET-0828437 Anthamatten知识产权。微米、介孔和大孔聚合物极大地有益于组织工程学、光化学、微电子学、氢储存和气体分离领域。多孔聚合物通常通过聚合诱导相分离（PIPS）、热诱导相分离（TIPS）或其它相转化技术来生产。这项研究代表了传统的溶液或熔融相方法的偏离。目的是开发气相沉积聚合（VDP）作为一种可控的，环境友好的技术，生产多孔和微结构的聚合物。反应性单体和非反应性物质（致孔剂）将共同沉积到冷却的基板上，以迫使相分离并阻止动力学捕获的微米级和纳米级微结构。这一概念将通过两种途径进行研究：i）无定形聚合物的自由基链增长聚合和ii）刚性棒高性能聚合物的缩聚。对于这两种情况，反应物和致孔剂浓度将随时间系统地变化，以产生依赖于深度的形态和密度。这将为定制设计非对称膜提供新的途径。第二个目标是将观察到的形态与工艺条件和相行为模型机械地联系起来。为了实现这一目标，横截面分析的沉积膜将研究使用光学和电子显微镜技术。最初的实验集中在聚（甲基丙烯酸甲酯）作为一个系统来研究在致孔剂存在下聚合物的自由基生长。结果表明，薄膜可以从气相生长在一个可控的和可重复的方式。当引入低摩尔质量致孔剂时，发生相分离。为了研究缩聚反应，第二低压（~10-6托）VDP反应器已被重新配置用于聚酰亚胺前体与热降解致孔剂的共沉积。将使用p型酞菁染料（代替致孔剂）进行类似的实验以制造和测试聚合物稳定的光致变色剂。更广泛的影响。这项研究与潜在的应用有很强的联系。具体而言，微孔刚性棒聚合物的VDP将为1）全有机气体分离膜和储氢材料，2）与微电子加工的当前趋势兼容的低K介电材料，以及3）聚合物稳定的有机光致发光材料提供新的途径。 预计未来至少有一个方向的研究计划将从这项研究中产生。 研究还将导致本体聚合，相分离，并在微米厚的聚合物薄膜发生玻璃化的理解得到改善。 该研究将最终提高控制微米级膜特征及其一维空间分布的能力。 研究和教育的整合将通过实践应用项目的课程开发和本科和研究生课程的专题。 社区外展活动包括组织专业发展、绿色工程、为当地高中教师举办讲座。 这些讲座将突出环境问题和解决方案，并提供新的教学工具，以弥合现实生活中的问题和传统的教科书学习之间的差距。

CBET-0828437Anthamatten Intellectual Merit. Micro-, meso-, and macroporous polymers greatly benefit the fields of tissue engineering, photovoltaics, microelectronics, hydrogen storage, and gas separations. Porous polymers are often produced through polymerization-induced phase separation (PIPS), thermal-induced phase separation (TIPS), or other phase-inversion techniques. This study represents a departure from traditional solution- or melt-phase methods. The goal is to develop vapor deposition polymerization (VDP) as a controllable, environmentally sound technique to producing porous and micro-structured polymers. Reactive monomers and non-reactive species (porogens) will be co-deposited onto a cooled substrate to force phase separation and arrest kinetically trapped micro- and nano-scale microstructures. The concept will be studied via two avenues: i) radical chain-growth polymerization of amorphous polymers and ii) condensation polymerization of rigid-rod, high performance polymers. For both cases, reactant and porogen concentrations will be systematically varied with time to create depth-dependent morphologies and densities. This will enable new routes to custom-designing asymmetric membranes. A second goal is to mechanistically relate observed morphologies to process conditions and to models of phase behavior. To achieve this, cross-sectional analysis of as-deposited films will be studied using optical and electron microscopy techniques. Initial experiments have focused on poly(methyl methacrylate) as a system to study free-radical growth of polymers in the presence of a porogen. Results indicate that films can be grown from the vapor phase in a controlled and repeatable manner. When a low-molar mass porogen is introduced, phase separatio occurs. To study condensation polymerization, a second low pressure (~10-6 Torr) VDP reactor has been reconfigured for co-deposition of polyimide precursors with thermally-degradable porogens. Similar experiments will be conducted using p-type phthalocyanine dyes (instead of a porogen) to fabricate and test polymer-stabilized photovoltaics. Broader Impacts. The research has strong connections to potential applications. Specifically, VDP of microporous rigid-rod polymers will provide new routes to 1) all-organic gas separation membranes and hydrogen storage materials, 2) low-K dielectric materials that are compatible with current trends in microelectronics processing, and 3) to polymer-stabilized organic photovoltaics. It is expected that future research programs in at least one of these directions will spawn from this study. Research will also lead to an improved understanding of bulk polymerization, phase separation, and vitrification occurring in micron-thick polymer films. The study will ultimately improve the ability to control micron-scale membrane features and their one dimensional spatial distribution. The integration of research and education will be through curriculum development of hands-on application projects and special topics in undergraduate and graduate-level courses. Community outreach activities include organizing professional development, Green Engineering, lectures for local high school teachers. These lectures will highlight environmental issues and solutions, and provide new teaching tools to bridge the gap between real-life problems and traditional textbook learning.