Preparation And Electro-deformation Of Nafion-metal Composites

As a new smart material, Ionic Polymer-Metal Composite (IPMC) could produce1arger displacement when stimulated by a low voltage. IPMC materials show great potential as soft robotic actuators, artificial muscles, and dynamic sensors in micro-to macro size range, due to their unique properties including simple actuating mode, high efficiency, low actuat voltage, safe operation and light weight. Based on the molecular structure of the substrate material of IPMC,Ag/Nafion based IPMC (Ag-IPMC) and Ni/Nafion based IPMC (Ni-IPMC) were successfully fabricated by penetration reduction process based on Nafion-117 film.A new Nafion-based IPMC was prepared by penetration reduction process at first, then the fabrication process, mechanism and influence factors of IPMC were studied. Characterized with IPMC the surface and cross-section morphology, the sectional element distribution was examined by scanning electron microscopy and energy dispersive X ray spectrometer, respectively. The physical properties of IPMC were studied in detail, including water uptake, surface resistance. Results showed that Ag-IPMC stable during the fabrication process by penetration reduction, while Ni-IPMC self-decompose easily. SEM pictures proved that the densification and planeness of twice chemical reduction were better than one. The microstructure of IPMC showed metal particles penetrated inside Nafion membrane with gradient distribution throughout the membrane. The water uptake property of IPMC increased with increasing temperature.At last, the electrodeformation performance of IPMC was studied with the influence factors of applied voltage, deformation current, and water loss rate, electrode thickness. The calculation formula of IPMC strain-stress was set up based on a cantilever beam model. The relation of the deformation displacement and voltage showed that the maximum deformation displacement increased as the applied voltage increasing. The electrodeformation repeatability would be excellent when the applied voltage was less than 7V. The increase spread of IPMC electrodeformation was reduced when continually increasing input voltage. The deformation displacement increased with the input voltage increasing and reached to its maximum value when the input voltage was up to a certain value.The relation of the deformation current and time showed that current first very quickly and then slowly when the input voltage was a certain value. The electrodeformation performance of IPMC could be improved by coating an oil cover in order to reduce water loss rate. IPMC with different electrode thickness were prepared by several chemical reductions. End export force and bending stress of IPMC increased with increasing electrode thickness. The Ag-IPMC with 23.8μm electrode thickness exhibited higher bending stress with its maximum value of 4.5MPa, Ni-IPMC with 20.15μm electrode thickness exhibited bending stress with its maximum value of 3.52MPa when they were actuated by the same input voltage.The studies results indicated that Ag-IPMC and Ni-IPMC show better electrodeformation performance under applied voltage input, and it could be used as a new IPMC material. But there are some problems to resolve, such as how to prepare suitable IPMC, how to improve electrodeformation level and the deformation characterization.