Core-Shell-Structured Copolyaniline-Coated Polymeric Nanoparticle Suspension and Its Viscoelastic Response under Various Electric Fields

Semi-conducting poly(n-methylaniline) (PNMA)-coated poly(methyl methacrylate) (PMMA) composite nanoparticles were synthesized using cross-linked and grafted PMMA particles as a core, and then, the PNMA shell was coated via chemical oxidative polymerization on the surface of modified PMMA nanoparticles. Their electroresponsive electrorheological characteristics when dispersed in silicone were confirmed under applied electric fields using a rotational rheometer, focusing on their viscoelastic response. Using a frequency sweep test, the frequency dependence of both the storage and loss moduli was confirmed to increase upon increasing the electric field, with a stable plateau regime over the entire angular frequency range.