Abstract: The modified hydrolysis method was employed to prepare modified TiO_x/acrylamide particles doped with chromium ions. XRD, TEM and particle size characterization results indicate that the particles are amorphous, and the average particle size is 140nm. The ERF possesses an optimum property when the Cr/Ti molar rate is 10%, under 4kV/mm DC electric field, the static shear stress can reach 152kPa. The mechanic property of ERF is enhanced remarkably due to the good wettability between particle and silicon oil, which results from the decrease of particle size caused by the synergetic effect of employment of Cr ions and SDBS synchronously. The ERF also shows a very good dispersion stability.

Key words: size effect, Cr ions modified, wettability, sedimentation