Efeect of three functional groups on electrorheology

Electrorheology (ER) was studied for 3 fluids consisting of dispersoids hav ing different functional groups and the same alkyl chain (C16H33-X; X= -OH, COOH, -CN) dispersed in dimethylsilicone oil. Fluids changed from disperse d 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 th eir ER effect and Delta epsilon ' increased with temperature below their me lting points, becoming almost ten, above their melting points. The ER effec t of-OH was the highest and that of-CN lowest. The ER effect of fluids were largely explained by Delta epsilon ', the difference in dielectric constan t epsilon ' at 10(2) and 10(5) Hz.