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

Case Western Reserve University, Cleveland OH

Investigators

Abstract

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.