A probabilistic model for estimation of ionically permeable inhomogeneities in polymer coatings

The mechanism of ionic conduction through polymer coatings has been investigated. The presence of highly permeable areas in the coating (designated as D type areas), impose an electrochemical inhomogeneity which is identified by change in the ionic resistance as measured by DC method. The effect of coating thickness was studied on D type behaviour of coatings. A structural model is proposed to explain the changes in conduction mechanism by variation of coating thickness. Statistical models based on numerical (simulation-based) and analytical (probabilistic model) analysis of D type areas distribution have been advanced to estimate the number of D areas in any given coating based on the percentage of D type. Using these models the number of permeable (D type) areas can be estimated based on the D type percentage of the coating.