PURPOSE: To obtain the title compsn. generating a large shear stress by applying a relatively weak electric field and having an excellent stability of the generated shear stress with the elapse of time by dispersing specified particles as a dispersed phase in an electrically insulating dispersing medium.

CONSTITUTION: 100 pts.wt. sulfonated polymer particles obtd. by sulfonating arom. rings of a crosslinked polymer obtd. by polymerizing 5.0mol% or more vinyl arom. compd. having at least one alkoxy group in the arom. ring (e.g. methoxystyrene), 0.1-50.0mol% polyvinyl compd. (e.g. divinylbenzene) and, if necessary, other vinyl compd. (e.g. styrene) in the presence of a polymn. initiator at 50-100°C for 2-40hr are incorporated with 10 pts.wt. or less water to obtain particles as a dispersed phase with a particle diameter of 0.1-100μm. Then, 100 pts.wt. said particles are dispersed in an electrically insulating dispersing medium (e.g. polydimethylsiloxane).