Solvent-Free Conjugated Polymer Fluids with Optical Functions

Abstract

Abstract Solvent-free fluidic materials possessing optoelectronic functions are expected to be major components in soft electronics applications. Conjugated polymers are promising targets for this purpose and their design approaches are classified into three types with respect to their structure: conjugation breaking (Type I), copolymerization with flexible polymers (Type II), and side chain engineering (Type III). In this short review, we highlight several early attempts to produce Type III conjugated polymers. We also present fully characterized Type III fluids recently developed by our group, with a brief summary of the structure–property relationship and fluidity-oriented functions. Introduction 1 Polymer Design 1.1 Fluidity of Polymeric Materials 1.2 Type III CPs with T g < 25 °C 1.3 Fluidification of Polyfluorenes 1.4 Effect of Side Chain Length 2 Fluidity-Oriented Functions 2.1 Mechanofluorochromism 2.2 Consistent Luminescence in Wide Range of Elastic Moduli 2.3 Prediction of Viscoelasticity Conclusions and Outlook