Development of Novel Nano-systems for Electrochemical Devices by Hierarchizing Concentrated Polymer Brushes

Abstract

This chapter provides an overview of the fundamental concepts concerning the synthesis and properties of a “concentrated” polymer brush (CPB) followed by our recent research topics regarding self-organization of CPB-modified nanoparticles, their application to solid electrolytes along with ionic liquids, and then their practical use in various electrochemical devices including a lithium ion battery, an electric double-layer capacitor, a dye-sensitized solar cell, and a polymer electrolyte fuel cell. A CPB is one type of polymer brushes, and its controlled synthesis and hence systematic study were achieved by living radical polymerization (LRP) or reversible-deactivation radical polymerization. Since the graft chains of CPB have a highly elongated and oriented conformation in a good solvent, and hence potentially, the CPB exhibits favorable characteristics on their own. However, the LRP method has a limitation in the range of the controllable molecular weight of thereby synthesized polymers and hence the thickness of CPBs, i.e., on the order of 100 nm, limiting their use for a wider range of applications. In order to overcome this issue, CPBs have recently been successfully built up to a new hierarchical nano-system via self-ordering, as building blocks, nanoparticles/rods/sheets with CPBs on their surfaces. Among others, we here focus on the science and technology of CPB from the viewpoint of above-mentioned applications, otherwise difficult to achieve high performance.