As shown in the investigations [15e17] the dependence of membrane conductivity on the water concentration can successfully be described by the equation of the percolation theory. The basic ideas of this theory were formulated by Broadbent and Hammersly in 1957.According to the percolation theory, after reaching some critical volume fraction of the conducting phase fc, the conductivity of a composition consisting of dielectric and conductor dramatically begins to grow with the increasing fraction of this phase. This change from dielectric to conductor has been called the percolation transition and the critical content of the conducting phase fc is a threshold of the percolation. At f>fc the dependence of the conductivity on the conducting phase fraction is described by the equation