Fabrication And Properties Research Of Actuators Based On Conducting Polymer

Electrochemical actuators have promising potential applications in the fields of micro-electromechanical systems (MEMS) and biomechanical biomedicine. Preparation of composite materials based on micro/nano-structured conducting polymer and furthur fabrication of electrochemical actuators is an important research field, which has great value of both theoretical research and practical application. The doping-dedoping (oxidized-reduced) process of conducting polymer accompany with the exchange of contra ions, solvent, andπelectrons, and the chain repulsion because of same charges, which result in the reversible changes of length, volume, color, and mechanical property of the polymer. Therefore, actuators based on the change of volume and mechanical property during the redox process of intrinsic conducting polymer (electrochemomechanical deformation) has attracted a great deal of attention. In this dissertation, two types of electrochemical actuators made of polypyrrole (PPy) film and working in aqueous electrolyte solution have been fabricated and their actuation behavior has been investigated.1. A simple, cheap, and feasible method of fabricating monolithic actuator has been developed. Through creatively introducing TiO2 nanoparticles, the actuator based on a monolithic PPy-TiO2 nanoparticles composite film has been electrochemically synthesized in dodecylbenzene sulfonic acid aqueous solution. Introducing very little amount of TiO2 nanoparticles into the PPy film matrix changed its structure and properties, therefore, the film had anisotropic structure. Monilithic PPy-TiO2 film could bend in two directions under very low driving potential, and has large bending angles, fast bending rate, good flexibility, and high mechanical strength. Moreover, the film made by continuous electrochemical deposition had good continuity in its morphology and structure, which avoided the delamination and improve the stability and lifetime.2. Through creatively introducing micro/nano-structure into conducting polymer actuators, two types of actuators based on brush-like composite film containing one layer of aligned PPy nanotubles and one layer of compact PPy film have been fabricated by two different methods. Actuator 1 - PPy(pTS-DBS): made by polycarbonate porous membrane template, containg one layer of pTS- (p-toluenesulfonate) doped PPy aligned nanotubles with close ends and one layer of compact DBS- doped PPy film. Actuator 2-PPy(DBS-DBS): made by alumina porous membrane template, containing one layer of DBS- doped PPy aligned nanotubles with open ends and one layer of compact DBS- doped PPy film. The anisotropic (asymmetric) structure and the high conductivity of compact PPy film made the actuator have good actuation ability. Above all, the research of the special function of the two micro-structured composite film actuators found that they could seize and transfer small objects such as microparticles from aqueous dispersions and transfer the objects into another medium by ultrasonication. This function has also promising application in transferring organisms such bacteria and cells.