Development of Fluid Devices for Soft Machine by the Use of Electro-sensitive Fluids

电流变液是一种在电场作用下从牛顿流体迅速转变为刚性固体的悬浮液。绝缘油在高电场中产生的二次流称为电流体动力效应。本研究的目的是建立一套适用于软机械的新型流体装置，如液体马达、微型泵等的设计方法。(1)开发了两种类型的电流变液。一种是介孔二氧化硅（MPS）悬浮液，ER效应？这通过将铜酞菁掺杂到二氧化硅表面的中孔中而得到显著改善。另一种是聚合物共混粒子的悬浮液。两种不具有ER活性的聚合物的共混物可以增强ER效应。(2)当放置在梳状图案电极上的ER悬浮液通电时，从光滑表面产生具有波形的精细图案。表面轮廓可以用单个正弦波或它们的叠加来近似。表面变形可以通过电泳力和电流变力的组合效应来表示。(3)电流变悬浮液被夹在两个具有径向线图案的扁平圆盘电极之间。通电方式的改变导致电极运动。电极的平行运动可以主动调节，因此这种技术在应用于新型ER马达时非常有吸引力。（4）众所周知，绝缘油在高电场中会引起EHD流动，但我们已经成功地产生了水的EHD射流，并开发了新的喷墨设备。虽然油液的EHD流动速度只有几cm/s的量级，但通过计算机模拟，可以定量地预测速度为1 m/s的EHD射流

The suspensions which undergo a rapid transition from Newtonian liquids to rigid solids on the application of electric fields, are referred to as electrorheological(ER) fluids. The secondary flow induced for insulating oils in high electric fields is called electrohydrodynamic (EHD) effects. The purpose of this study is the establishment of design method for new fluid devices such as liquid motor and micro pump, which can be applied to soft machines. (1) Two types of ER fluids are developed. One is the mesoporous silica(MPS) suspensions, the ER effect of? which is drastically improved by doping of copper phthalocyanine into mesopores of silica surfaces. The other is the suspensions of polymer blend particles. The ER effects can be enhanced by the blend of two polymers which are not ER-active. (2) When the ER suspensions which are placed on the comb pattern electrodes, are electrified, a fine pattern with a waveform is developed from the smooth surface. The surface profiles can be approximated by single sinusoidal waves or their superposition. The surface deformation can be expressed by a combination effect of electrophoretic and ER forces. (3) The ER suspensions were sandwiched between two flat disc electrodes with the radial line patterns. The change in electrification mode led to a motion of electrode. The parallel motion of electrodes can be actively regulated and therefore this technique is very attractive in application to new ER motors (4) It is well known that the EHD flow is induced for insulating oils in high electric fields, but we have succeeded in generating the EHD jet for water and developed the new ink jet devices. Although the velocity of EHD flow for oils is of the order of several cm/s, the EHD jet with a velocity of 1m/s can be quantitatively predicted by computer simulation