Two-phase equilibrium model of insulator–insulator contact charging with electrostatic potential

A two-phase equilibrium model based on an ideal gas of singly charged ions in equilibrium with a submonolayer adsorbed film was developed to describe the pressure dependence of insulator–insulator contact charging. Experimental data show that the surface charge density decreases with respect to pressure for insulators as pressure is lowered. In this work, the gas phase of the two-phase model is extended to consider the electrostatic coulombic and screening potentials from the surface.