Interactions between two similar plane parallel double layers for Na3PO4 type asymmetric electrolytes at positive surface potential

Abstract

The interaction between two similar plane double-layers for Mg3(PO4)2 type asymmetric electrolytes was investigated with the aid of λ parameter method. The interaction energies for the system at positive surface potential were expanded in power series at low and high potential, respectively. The accurate numeral results and V′-ξ d curves were given for y 0 ≤ 20 and they can be used to check up the validity of approximate expressions obtained. When y 0 ≥ 5, V′ hardly changes with y 0. The interaction energies between two similar plane parallel double layers for symmetric and asymmetric electrolytes at y 0 = 1 were compared; when ξ d is small, the interaction energies for Mg3(PO4)2 type electrolytes increase more drastically than for other type electrolytes. The present results are also fit for Al2(SO4)3 type asymmetric electrolytes at negative surface potential.