Materials World Network: Collaborative Research: Nanoscale Self-Assembly of Well-Defined Binary Mixed Homopolymer Brushes Grafted on Inorganic Particles

该合作项目旨在了解由两种不同的均聚物随机或交替通过共价键固定在无机颗粒上组成的二元混合刷的相行为，并探索其在聚合物纳米复合材料中的应用。混合刷是一类有趣的环境响应材料。为了充分挖掘它们在各种技术应用中的潜力，有必要了解它们在不同环境条件下的相行为。为了满足这一需求，一个国际合作小组已经成立，由赵斌（田纳西大学的聚合物化学家），朱磊（凯斯西储大学的聚合物物理学家），冯秋和唐平（中国复旦大学的理论家）组成。通过结合两种不同的“活”/可控聚合技术，PI将制备混合刷与预定的分子量，窄的多分散性和控制接枝密度从不对称的双官能引发剂终止的自组装单分子层固定在各种无机粒子。本文将采用实验和计算机模拟相结合的方法对混合刷的相形貌进行系统的研究。将阐明各种分子参数如分子量和接枝密度的影响。混合刷接枝颗粒将用于制造具有改进性能的先进聚合物/无机纳米复合材料。从这项工作中获得的知识可以在制备新型纳米结构杂化材料和二元混合聚合物刷在技术用途中的应用方面开辟新的机会。这个合作项目汇集了来自美国和中国三所大学的科学家，研究生和本科生，他们具有不同的背景和专业知识。两国之间的教师和学生交流使他们接触到不同的研究环境和文化，并使他们能够获得科学方面的国际经验和全球视野。这项研究为培养学生在高分子和有机合成，表面化学，以及高分子物理。PI致力于帮助K-12教育中的科学和工程教学，与当地高中教师合作，开发科学和技术课程的新模块和实验室实验，重点是聚合物表面化学。高中教师和代表性不足的少数民族高中学生将在夏季举办，目的是提高高中教师，教学成绩和提高学生对科学和工程的兴趣。

This collaborative project seeks to understand the phase behavior of binary mixed brushes composed of two distinct homopolymers randomly or alternately immobilized via covalent bonds on inorganic particles and to explore their applications in polymer nanocomposites. Mixed brushes are an intriguing class of environmentally responsive materials. To tap into their full potentials in various technological applications, it is necessary to understand their phase behaviors under different environmental conditions. In response to this need, an international collaborative team has been assembled and consists of Bin Zhao (a polymer chemist at University of Tennessee), Lei Zhu (a polymer physicist at Case Western Reserve University), and Feng Qiu and Ping Tang (theoreticians at Fudan University, China). By combining two different "living"/controlled polymerization techniques, the PIs will prepare mixed brushes with predetermined molecular weights, narrow polydispersities and controlled grafting densities from asymmetric difunctional initiator-terminated self-assembled monolayers immobilized on a variety of inorganic particles. The phase morphologies of mixed brushes will be systematically studied using both experimental and computer simulation approaches. The effects of various molecular parameters such as molecular weight and grafting density will be elucidated. The mixed brush-grafted particles will be used to make advanced polymer/inorganic nanocomposites with improved properties. The knowledge gained from this work could open up new opportunities in the preparation of novel nanostructured hybrid materials and the applications of binary mixed polymer brushes in technological uses.This collaborative project brings together a group of scientists, graduate and undergraduate students with various backgrounds and expertise from three universities in the U.S. and China. Exchange of faculty and students between the two countries exposes them to different research environments and cultures, and enables them to gain international experience and global visions in science. This research provides a good opportunity to train students in polymer and organic synthesis, surface chemistry, as well as polymer physics. The PIs are committed to help science and engineering teaching in K-12 education by working with local high school teachers to develop new modules and lab experiments in science and technology classes with an emphasis on polymer surface chemistry. High school teachers and underrepresented, minority high school students will be hosted in the summer with the goals of improving high school teachers, teaching performance and enhancing student interest in science and engineering.