Monte Carlo simulation of ion transport of high strain ionomeric with cluster morphology

摘要

The transport of charge due to electric stimulus is the primary mechanism of actuation for a class of polymeric active materials known as ionomeric polymer transducers (IPT). Due to the fact that a universally accepted morphological model for the structure of Nafion has not been defined, this initial work is aimed to investigate the relationship between ion transport performance inside Nafion and the cluster morphology. A two-dimensional ion hopping model has been built to describe ion transport in IPT with Monte-Carlo simulation. In the simulation, a 50nmx50nmx 1nm lattice holds 200 cations and 200 anions. The initial distribution of anions is varied from uniformly random distribution to one with 15 clusters, 8 clusters and 4 clusters. A step voltage is applied between the electrodes of the IPT, causing thermally activated hopping. Periodic boundary conditions are applied when ions hop in the direction perpendicular to the electric field. The influence of the electrodes on both faces of IPT is presented by the method of image charges. The results of current response, charge density and ion distribution are compared for different initial ion distributions.