The Basic Electrical Properties Of Platinum Ionic Polymer Metal Composite(Pt-IPMC)

As a n ew type of smart materials,Ionic Polymer Metal Composite(IPMC)show not only excellent driving performance but also good sensing capacity.They have potential applications in areas such as medicine,bionics and microelectromechanical systems.This paper is focused on the theoretical and experimental study of basic electrical property.The main work and results are summarized as follows.We first manufactured Pt-IPMC,Ag-IPMC and Pt-MWCNTs-IPMC using the electroless deposition method.Various properties were then characterized for them: The changes of moisture content over time was measured at room temperature and under atmospheric pressure;The elastic modulus of was determined by tensile test;The storage modulus and loss modulus at different frequencies and temperatures were obtained from dynamic mechanical experiments;And the distribution of electrodes in IPMC was determined by EDS.In general,the Pt-IPMC shows the best performance and was the focus of this paper.To study the basic electrical properties of the Pt-IPMC,we measured the impedance and probed its dependences on electrode and interface for Pt-IPMC samples immersed in sulfuric acid or deionized water.A model consisting of surface resistance,diffusion layer capacitance,and Warburg impedance element was built based on the electrical double layer model.The model incorporated the process of ion migration and diffusion,and the electrode(platinum metal particles)gradient distribution form in the membrane.We found that the output voltage increases as surface resistance decreases,and the response time increases as the capacitance of the diffusion layer increases.To investigate the electrical response of the Pt-IPMC,we measured the output voltages in step and sinusoidal excitation and used the four point bending beam to evaluate the bending moment.We found that the output voltage was delayed significantly and the sensitivity was up to 3.5558mV/2000?? at the frequency of approximately 5Hz.A electrical response model of IPMC was made based on two relations.One is the relation between bending curvature and pressure according to the large deformation theory.The other is the linear relation between the bending curvature and the output voltage given by the irreversible thermodynamics theory.Our results demonstrate that the model can satisfactorily predict the output voltage response to the bending.Finally,to explore the potential applications of the IPMC,the open circuit voltage and short circuit current were measured in sinusoidal periodic excitation.With simulations we compared the charge output changing law.We found that the maximum power transfer is obtained by selecting a matching load admittance.To summarize,in this paper we focused on the basic electrical properties of the IPMC and the electrical response of bending IPMC was get by simulation and experiment.These results provide the necessary experimental and research basis for promoting the development of IPMC as a functional device.This work is funded by the National Natural Science Foundation of China under contract(Grant number: 11372132).