Conducting poly(N-methylaniline)-coated cross-linked poly(methyl methacrylate) nanoparticle suspension and its steady shear response under electric fields

Abstract

Abstract Core–shell-structured poly(methyl methacrylate) (PMMA)/poly(N-methylaniline) (PNMA) composite particles were fabricated using a facile method and their electrorheological (ER) characteristics under applied electric fields were examined. Initially, monodisperse PMMA nanoparticles were obtained using a dispersion polymerization method. Subsequently, the PNMA shell was coated by chemically oxidative polymerization. For this purpose, the surface of PMMA was modified by glycidyl methacrylate, ethylene glycol dimethacrylate, and oxydianiline as swelling, cross-linking, and grafting agents, respectively. The ER performance of the chain-like structures of PMMA/PNMA microparticles, when dispersed in silicone oil, was observed by optical microscopy. The ER properties were investigated using a rotational rheometer to examine the effects of applied electric fields, focusing on the steady-shear response, and specifically the Cho–Choi–Jhon model was used to describe the flow curves of the particles over the entire shear-rate region.