Chain Dynamics and Layering within Polyelectrolyte Multilayer Films

逐层（LbL）多层膜的分层是多层膜（PEM）的先进生物医学和光学应用的核心，但经常受到分子扩散和混合的影响。在这个项目中，聚合物链的动力学和PEM的内部结构之间的基本相关性将被探索，这些知识将被应用于开发分层LbL PEM膜的构建策略，并研究其结构在老化过程中的演变。 具体而言，将在三种情况下探索链间动力学：（1）在溶液中;（2）在多层构造期间溶液与膜之间;以及（3）在LBL膜在潮湿或水性环境中老化期间的后组装步骤。将分别对情况（1）-（3）应用荧光相关光谱（FCS）、FCS和原位ATR-FTIR的组合以及图案光漂白后荧光恢复（FRAPP）和中子反射率（NR）的组合。该项目涉及通过离子配对或氢键结合合成定义明确的多碱-多酸（PB-PA）对。中心的建议是，平移扩散的聚合物内PEM是各向异性的，和拟议的实验旨在揭示这种各向异性的程度，以及如何随着时间的推移，这种各向异性的演变时，PEM薄膜在高湿度环境中老化，或在水溶液中，在不同的温度和/或离子强度。在这个建议中产生的知识可以用来预测的相互作用，运动，弛豫和秩序在广泛的PEM films.NON-TECHNICAL摘要：这个项目提供了自组装聚合物薄膜的动力学和结构的知识，这将使建设和预测的分层聚合物薄膜的生物医学和光学应用的老化。一个实例包括能够从生物医学装置或植入物的表面顺序递送治疗性化合物的聚合物涂层。重要的是，该项目将为参与聚合物科学前沿问题的研究生和暑期本科生创造一个肥沃的培训基地，通过与NIST和ORNL的合作进一步丰富了培训基地。纳米结构聚合物的新课程将作为高度跨学科的史蒂文斯纳米技术研究生课程的一部分开发。该项目的一个重要组成部分包括与来自北方新泽西地区的高中生合作，并通过涉及K-12高中生的实验示范和海报展览传播知识。通过与K-12 ACS SEED和科学计划NJ计划的合作伙伴现有的密切联系，将开发一个新的教育计划。具体来说，通过与最近开始的NSF资助的GK-12计划，新泽西工程教育联盟（NJAEE），并与史蒂文斯中心工程和科学教育创新（CIESE），我们生活中的教学模块聚合物将在高中环境中建立和试点。该模块将在NJAEE网站上展示，并链接到CIESE网站，每年有数十万K-12教育工作者和学生访问该网站。

TECHNICAL SUMMARY:Stratification of layer-by-layer (LbL) polyelectrolyte films lies in the heart of advanced biomedical and optical applications of polyelectrolyte multilayer (PEM) films, yet is often compromised by molecular diffusion and intermixing. In this project, fundamental correlations between dynamics of polymer chains and internal structure of PEMs will be explored, and this knowledge will be applied to develop strategies for the construction of stratified LbL PEM films and to study evolution of their structure during aging. Specifically, inter-chain dynamics will be explored in three cases: (1) in solution; (2) between solution and the films during multilayer construction; and (3) at a post-assembly step during aging of LBL films in humid or aqueous environments. Fluorescence correlation spectroscopy (FCS), a combination of FCS and in situ ATR-FTIR, and a combination of fluorescence recovery after pattern photobleaching (FRAPP) and neutron reflectivity (NR) will be applied for cases (1)- (3), respectively. The project involves synthesis of well-defined polybase-polyacid (PB-PA) pairs associated through ionic pairing or hydrogen-bonding. The central suggestion is that translational diffusion of polymers within PEMs is anisotropic, and proposed experiments aim to reveal the degree of this anisotropy as well as how this anisotropy evolves with time when PEM films are aged in high humidity environment or in aqueous solutions under varying temperature and/or ionic strength. The knowledge generated in this proposal can be used to predict interactions, motions, relaxations and order in a broad range of PEM films.NON-TECHNICAL SUMMARY:This project provides knowledge of dynamics and structure of self-assembled polymer films, which will enable construction and prediction of aging of stratified polymer films for biomedical and optical applications. One example includes polymer coatings enabling sequential delivery of therapeutic compounds from the surface of a biomedical device or an implant. Importantly, this project will create a fertile training ground for the participating graduate students and summer undergraduate students in forefront issues of polymer science, a training ground further enriched by collaboration with NIST and ORNL. A new course on nanostructured polymers will be developed as part of the highly interdisciplinary Stevens Nanotechnology Graduate Program. A significant part of the project includes working with high school students from the Northern New Jersey area and disseminating knowledge through experimental demonstrations and poster exhibition involving K-12 high school students. Through existing close links with the K-12 ACS SEED and the Partners in Science Program NJ program, a new educational initiative will be developed. Specifically, by working with a recently started NSF-funded GK-12 initiative, New Jersey Alliance for Engineering Education (NJAEE), and with the Stevens Center for Innovation in Engineering and Science Education (CIESE), a teaching module Polymers in Our Life will be built and piloted in a high school setting. The module will be featured on the NJAEE website, and linked to the CIESE website, which enjoys hundreds of thousands of site visits by K-12 educators and students each year.