Studies On The Synthesis And The Electrorheological Effect Of SrTiO₃/PANI Compersite Particles

Electrortheological (ER) fluids are a kind of smart materials that have the ability to increase their viscosity rapidly and reversibly in the presence of an electric field. This rapid response and reversible change make it possible to apply the fluid in switch, brakes, clutch, valve and other intelligence-control areas.In this thesis, hydrolysate of Ti compound was reacted chemically with soluble Sr salt (SrCh) in alkalinous solution to directly produce ultra-pure and superfine SrTiO3 powder. In addition, the strontium titanate (BrTiCbVpolyaniline composite particles were synthesized by the oxidization Polymerization of Aniline in the inversed emulsion polymerization technique. The SrTiOs and the composite particles were characterized using different techniques such as XRD, TEM and FTIR. Dispersing the obtained particles in silicon oil or other base media, electrortheological fluids are obtained, which exhibit ER effect individually. The influence of the chemical composition of the particle including the content of PANI, the doping degree of PANI, the oxidizer account during ANI polymerization and its adding sequence, the water content in the particle on the ER effect of the composite particles in silicone oil were studied. The paper also showed the ER effects of the fluid at different particle shape, and size, varying particle content and so on.Besides the influence of particle properties, this paper discussed the influence of base oils with different permittivity, and some meaningful conclusions were attainedAlthough the surfactant can improve the dispersing stability of ERFs, its influences on ER effect are different. These kinds of surfactants including 0 n -10, spanSO, MOA3 and KH-550 were chosen to illustrate their effects on the ER effect of the composite particles. It was foundthat O n -10 can increase the ER effect the composite particle, while the other two can't,Studying the relationship between shear stress and shear rate in the presence of an electric field. We found that the fluids showed pseudo plastic behavior under direct field.