Conducting polymers charge transport models

Charge transfer kinetics for electronically conducting polymer formation, 583 Charge transport in polymers, 567 Chemical breakdown model for passivity, 236... 

The electrolyte concentration is very important when it comes to discussing mechanisms of ion transport. Molar conductivity-concentration data show conductivity behaviour characteristic of ion association, even at very low salt concentrations (0.01 mol dm ). Vibrational spectra show that by increasing the salt concentration, there is a change in the environment of the ions due to coulomb interactions. In fact, many polymer electrolyte systems are studied at concentrations greatly in excess of 1.0 mol dm (corresponding to ether oxygen to cation ratios of less than 20 1) and charge transport in such systems may have more in common with that of molten salt hydrates or coulomb fluids. However, it is unlikely that any of the models discussed here will offer a unique description of ion transport in a dynamic polymer electrolyte host. Models which have been used or developed to describe ion transport in polymer electrolytes are outlined below. 

The Poisson equation can also be used in modelling - charge transport phenomena in - semiconductors and -> conductive polymers [iv, v]. 

Polaron — Polarons are charged quasiparticles with spin lf. This term has been introduced by physicists as one of the possible solutions to the equations of the relevant defect model of solids in order to describe an electron in a dielectric polarizing its environment (electron-phonon coupling), electrically situated below the conduction band, and transported together with its polarized environment. Polarons and -> bipolarons are the charge carriers in oxidized or reduced (doped) -> conducting polymers. A polaron is defined as a neutral and a charged -> soliton in the same... 

The conductivity is a solid-state phenomenon, and, as pointed out already, conductivity is not a single chain phenomenon. The band-gap description of a conjugated chain is a one-dimensional model. Additionally, considerably interchain charge transport is necessary to describe a metal-like behavior in the highly doped three-dimensional sample and further transfer mechanisms across the polymer chains have to be discussed. What one actually needs to know in explaining conductivity of organic polymers is how the charge transport proceeds... 

A last important aspect of these functionalized conducting polymers concerns their interest for the theoretical modelling of the mode of operation of modified electrodes. Previous work based on redox polymer coated electrodes raised a fundamental question concerning the transport of charge in these polymeric materials. 

As discussed in previous sections, the mechanisms for the formation of metallic state and charge conduction in conducting polymers have been the subject of intensive study since the occurrence of an insulator to metal transition was reported upon doping. It is proposed that non linear defects such as polarons, solitons and bipolarons have a major role in these systems [36, 95-97]. In earlier synthesised conducting polymers, inhomogeneities often dominated the transport properties, and metallic island models were proposed to... 

---