The percolation behaviour of electret at presence of water condensation

The time stability of the surface potential of PTFE and silicon dioxide electrets at room temperature are similar: after an initial small decay the potential is practically constant during a time interval that decreases as humidity increases and then drastically drops. The time stability of the surface is correlated with potential relief of an electret sample. The presence of charge on a dielectric surface stimulates the process of water condensation. The behavior of electrets in a wet atmosphere is explained in terms of the percolation model that includes the process of nucleation and growth of conductive clusters. A theoretical consideration within a framework of this model and experimental results are presented