Electrical and electrorheological behavior of poly(aniline-co-1,4-phenylenediamine) suspensions

Suspensions of protonated poly(aniline-co-1,4-phenylenediamine) copolymers and corresponding bases in silicone oil have been investigated in a DC electric field. Low-voltage measurements were performed with conducting protonated copolymers. Under these conditions, time dependences of the current passing through suspensions at various field strengths reflected very sensitively the formation of chains of polarized particles in the electric field. The dielectric and high-field-strength electrorheological (ER) measurements of suspensions of non-conducting copolymer bases showed that both ER efficiency and particle dipole coefficient characterizing particle polarizability decreased with the reduction of the aniline content in the copolymer. Relations between suspension viscosity and Mason number have been compared for copolymers of various compositions. The highest ER performance was obtained in suspension of polyaniline base. (C) 2000 Elsevier Science Ltd. All rights reserved.