包覆表面活性剂的TiO_2电流变液

ELECTRORHEOLOGICAL BEHAVIOR OF THE SUSPENSIONS OF SURFACTANT COATED TiO_2

利用 Ｗ／Ｏ微乳液法，分别由水／Ｓｐａｎ８０或 ＤＢＳ／正戊醇／环己烷形成 Ｗ／Ｏ 微乳液，将钛酸盐在微乳中以水核为中心水解，制得包覆表面活性剂的ＴｉＯ２粒子．包覆表面活性剂可显著提高ＴｉＯ２的电流变活性，且非离子型表面活性剂的效果远好于离子型表面活性剂．一种典型的颗粒／硅油体积比为 ３１％的电流变液在 ３ｋＶ／ｍｍ直流电场下的剪切应力为 １．４ｋＰａ，约为纯 ＴｉＯ２的 ３倍，漏电流密度小于 ２５μＡ／ｃｍ２．当 Ｓｐａｎ８０与 ＴｉＯ２的质量比为 ７％～１３％时有最佳电流变效应．包覆适量的非离子表面活性剂可明显优化电流变液的温度效应，改善颗粒的悬浮稳定性．

In the micro--emulsion system of H2O/Span or DBS/n--amyl alcohol/xylene, the particles of TiO2 coated by surfactant are obtained. The Electrorheological (ER) behavior of the suspension made of TiO2 coated by surfactant in dimethylsilicone oil with a 31% volume fraction is investigated. The result showed that covering surfactant could increase the ER activity of TiO2. In the electrical field of 3kV/mm, the shear stress is about 1.4kPa, while the current density is only 25μA/cm2. This method has a better effect than that of adding surfactant in silicone oil simply. The content of coated surfactant had a strong influence on ER behavior. At the same time, because R = [H2O]/[Surfactant] could control particles' granularity and content of coated surfactant in the method of W/O micro--emulsion technique, the sedimentation could be controlled and modified by surfactant.