Study On Clapeyron Equation With Influence Of External Electric Field

Clapeyron Equation(C lapeyron Equation) is a basic equation on dealing with first order phase transition of one–components. It connects the phase transformation enthalpy, pressure and temperature, widely used in scientific research and engineering practices. Since it was found that the electric field can obviously effect phase equilibrium, more and more scientists set out to study this phenomenon. Some test different effect of different electric field on the saturated vapor pressure,the boiling point and the evaporation enthalpy of different materials; some find out the influence via computer. Although their work that can explain some phenomenon from some aspects, the inaccuracy of experiment and monotonicity of computer simulation, make the conclusion not so satisfactory. Even different scientific workers conclude opposite in a different way for the same kind of material.(1).To give the influence of electric field on the phase equilibrium more accurately and generally is a subject receiving much attention from the researchers. Based on the basic principle of phase equilibrium, classic clapeyron equation and theory of dielectrics this paper theoretically derived the general expression of the clapeyron equation under the action of electric field from the general expression of chemical potential. Take the basic physical and chemical properties of solid, gas and liquid into consideration, we can apply this equation in the liquid- gas, solid- gas and solid- liquid phase equilibrium. In the end, we take two typical materials for example to study their liquid-vapor phase equilibrium under electric field and conclude electric field can improve the boiling point and reduce the saturation vapor pressure for both materials. Applied in only one of the liquid phase and gas phase respectively, only when the electric field intensity reaches 1e6V/m and 1e9V/m can it has obvious influence on the phase equilibrium. With these conclusion consistent with most experiment and computer simulating work, our work of clapeyron equation under the action of electric field has considerable guiding significance for the related scientific research and engineering practice.