The Transport of an Ion through a Channel Formed by a Helical Electroactive Polymer

Abstract

The transport of a

ion in helical poly(3-octylthiophene) is simulated by conducting molecular dynamics in the absence, and in the presence, of electric fields along the channel direction. Temperature-dependent diffusion simulations show that the ions encounter an energy barrier of about 7 kJ mol^-1. The effect of the degree of oxidation of the polymer (atomic charges on the inner walls of the channel) on the ion migration shows that the rate of the transport increases with oxidation level until the polymer is about 50% oxidised. Above this figure the resulting motion becomes hindered by the high charges on the channel, which result in ion congestion and “sticking”. Also examined are the competing effects of solvent molecules in the channel and the radial distribution statistics which, in common with the migration studies, show that above 50% oxidation the polymer chain starts to undergo distortion from the helical configuration.

Keywords:

• Diffusion
• Migration
• Helical channel
• poly(3-octylthiophene)
• Activated ion transport