A new model for estimation of water uptake of an organic coating by EIS: The tortuosity pore model

In this work, a new and more intricate model of estimate water uptake inside an organic coating by impedance measurements is proposed, the tortuosity pore model (TPM). In this model, the organic coating (film) is considered to be a ternary system, composed of liquid (solution), solid (coating matrix) and gas (air) phases. Moreover, the pores tortuosity inside the coating is taken into consideration. Comparison between this new model and the other models found in the literature will be presented, showing that this new model presents for water uptake better correlation with the values obtained by gravimetry.