EFFECT OF THREE FUNCTIONAL GROUPS ON ELECTRORHEOLOGY

Abstract

Electrorheology (ER) was studied for 3 fluids consisting of dispersoids having different functional groups and the same alkyl chain ( C 16 H 33-X; X=-OH, -COOH, -CN) dispersed in dimethylsilicone oil. Fluids changed from dispersed to homogeneous with increasing operating temperature because dispersoids melted at higher temperatures. Both the ER effect and dielectric properties changed drastically with the change from dispersed to homogeneous. Both their ER effect and Δε′ increased with temperature below their melting points, becoming almost zero above their melting points. The ER effect of -OH was the highest and that of -CN lowest. The ER effect of fluids were largely explained by Δε′, the difference in dielectric constant ε′ at 102 and 105 Hz.