TiO2-doped Ionic Polymer-Metal Composite Actuator

Abstract

Ionic polymer metal composites (IPMCs) have received substantial attention in the past several years. IPMC actuators are capable of complex deformation in water and air and they are soft actuation materials with promising applications in wide range of fields, such as robotics and medical devices. Although fabrication techniques on the polymer doped with metal oxides for IPMCs have been developed, metal oxide doped ionic polymer membrane through sol-gel preparation has not been studied yet. This process makes the oxide particle well-distributed in the membrane compared to that of physical method to insert oxide particle into the ionic polymer membrane using hot pressing. In this thesis, the research is mainly focused on characterization of optical, physical, electrochemical and electromechanical properties of TiO2-doped ionic polymer membrane and IPMCs prepared by the sol-gel preparation. The structures of fabricated samples were investigated by Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and Differential Scanning Calorimetry (DSC). Also, water uptake, Dynamic Mechanical Analysis, and Electrochemical Impedance Spectroscopy (EIS) were carried out to confirm properties of fabricated samples. Furthermore, electromechanical behaviors of samples were tested, including actuation performance and blocking force measurement. X-Ray and UV-Visible spectra of the fabricated membranes indicate the presence of anatase-TiO2 in the modified membranes. Water uptake of TiO2-doped membrane with 0.16 wt% of doping level show highest value among the samples. In the Differential Scanning Calorimetry results, glass transition temperature increases with increasing the TiO2-content in the membrane. Storage modulus of dried TiO2-doped samples increases as increasing of amount of TiO2 in the samples, whereas storage modulus of hydrated samples are strongly related to level of water uptake. EIS measurements show that the conductivity of TiO2-doped IPMCs decreases with increasing the content of TiO2, in spite of internal resistance drop in the samples. Above all, bending displacements of TiO2-IPMCs is decreased as increase of TiO2-content in the samples, while blocking force of each sample is increased with increase of amount of TiO2.