Study of piezo-electric elastomer as tactile sensor of a robot

针对压电弹性体在机器人触觉传感器中的应用，研究了压电弹性体的制备及其物理性能。设计了空间电荷型（SC）、平行偶极子型（PD）和类橡胶棒聚合物共混型（RRB）三种压电弹性体。作为SC型弹性体，我们使用了掺有高氯酸锂和远旋聚二甲基硅氧烷（PDMS）的聚环氧丙烷（PPO）乳液，它们通过加热交联。首次研究了非交联体系在电场作用下的形貌变化。带电液滴向电极的迁移导致了空间电荷分布的偏差。在此基础上，在强电场作用下，通过交联PDMS制备了由PPO/PDMS组成的驻极体。弹性体表现出比聚偏氟乙烯更高的压电性。根据施加应力的方式，观察到复杂的压电信号，表明弹性体可以区分接触弹性体的物体。作为一种PD型压电弹性体，我们使用了异戊二烯-异戊二烯-苯乙烯三嵌段共聚物（SIS），其中异戊二烯嵌段具有平行于链轮廓方向的偶极子，而乙烯嵌段充当交联。SIS的介电测量结果表明，极化是由弹性块链从一个域跳到另一个域实现的。为了研究RRB型弹性体的极化率，我们对聚异氰酸己酯/聚异戊二烯/甲苯三元体系进行了介电测量。

Aiming an application to the tactile sensor of a robot, we investigated the preparation and physical properties of piezo-electric elastomers. Three types of piezo-electric elastermers were designed namely, space-charge type (SC), parallel dipole type (PD), and rubber-rod-like polymer blend type (RRB). As an SC type elastomer, we used an emulsion of poly (propylene oxide) (PPO) doped with lithiumperchlorate and telechelic poly (dimethyl siloxane) (PDMS) which cross-links by heating. The morphology change under an electric field was first investigated for uncross-linked system. The migration of charged droplets towards the electrodes resulted in a deviation of the distribution of space charge. Based on this observation an electret composed of PPO/PDMS was prepared by cross-linking of PDMS under a strong electric field. The elastomer exhibited piezoelectricity higher than that of poly (vinylidene fluoride). Complicated piezoelectric sygnals were observed depending on the manner of applying stress indicating that the elastomer can distingush objects on which are touching the elastomer. As a PD type piezo-electric elastomer, we used stirene-isoprene-sryrene triblock copolymers (SIS) in which the isoprene block has a dipole aligned in the direction parallel to the chain contour and the stirene block acts as the cross-link. The results of dielectric measurements of SIS indicate that polarization is achieved by jump of the stirene block chains from one domain to the other. To inverstigate the rate of polarization in an RRB type elastomer, we carried out dielectric measurements on poly (hexyl isocyanate) /polyisoprene/toluene ternary system.