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 elec tric field. Low-voltage measurements were performed with conducting protona ted copolymers. Under these conditions, time dependences of the current pas sing through suspensions at various field strengths reflected very sensitiv ely the formation of chains of polarized particles in the electric field. T he dielectric and high-field-strength electrorheological (ER) measurements of suspensions of non-conducting copolymer bases showed that both ER effici ency and particle dipole coefficient characterizing particle polarizability decreased with the reduction of the aniline content in the copolymer. Rela tions 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 righ ts reserved.