Novel approach to enhance the dispersion stability of ER fluids based on hollow polyaniline sphere particle

By this time, when electrorheological (ER) fluids were applied long term, these have been limited because of problems with particle sedimentation. To solve the sedimentation problem, we report on the preparation of hollow polyaniline (PANI) sphere with nano-scale as the disperse phase for estimating electrical and ER properties. A procedure has been developed to coat colloidal polystyrene (PS) core within a PANI shell by chemical oxidation polymerization. The core-shell particles can be turned into spherical hollow PANI shells by dissolution of the PS cores by using organic solvent. The sedimentation of prepared hollow PANI spheres with nano-sized particle in the silicone oil (50 cS) was observed using UV spectrum with time. Also, the suspension showed ER response and good dispersion stability in the silicone oil.