Electrorheology of conducting polyaniline composite particles

Abstract

Abstract Three different kinds of particles of semiconductive polyaniline (PANI), spherical poly(methyl methacrylate) with a PANI shell (PAPMMA), and conductive PANI encapsulated by insulating melamine-formaldehyde resin (MCPA) were synthesized and adopted as a dispersed phase for electrorheological (ER) fluids. ER fluids are suspensions of polarizable particles dispersed in non-conducting liquids. The rheological characteristics of ER fluids rapidly change in the presence of an applied electric field, which can be controlled by both the applied electric field strength and particle concentration with a fast response time on the order of milliseconds. MCPA-based ER fluids show the largest stress enhancement by an applied electric field compared with both PANI- and PAPMMA-based ER fluids, demonstrating that the conductive core with an insulating shell system is a better ER material than homogeneous, semiconductive materials or surface-semiconductive materials with insulating cores.