Emulsion‐polymerized polyindole nanoparticles and their electrorheology

ABSTRACT Polyindole (PIn) nanoparticles were synthesized through an emulsion polymerization technique in this study and then examined as an anhydrous semi‐conducting electro‐responsive material. Their surface morphology and chemical structure were observed with high‐resolution scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. When dispersed in silicone oil, the electrorheological (ER) properties of the PIn particles were examined using a rotational rheometer with both steady shear and oscillatory tests under various applied electric field strengths with direct observation using an optical microscope. Flow curves of shear stress as a function of shear rate were well fitted using the Cho‐Choi‐Jhon model. Dielectric analysis was also performed to examine the permittivity and loss factor in relation to the ER effect. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46384.