Solubility properties in polymers and biological media: 10. The solubility of gaseous solutes in polymers, in terms of solute-polymer interactions

Abstract

A general equation SP=SP 0+l log L 16+s(π 2 ∗+ dδ 2) + aα 2 + bβ 2 has been used to describe solubility properties of a wide range of gaseous solutes in polymers. The property, SP, may be a log V G value, an enthalpy of solution, etc., and the explanatory variables are solute parameters: L 16 is the Ostwald solubility coefficient of the solute on hexadecane at 25°C, π∗ 2 is the solute dipolarity, δ 2 a polarizability correction term, α 2 the solute hydrogen-bond acidity, and β 2 the solute hydrogen-bond basicity. Solubilities may then be discussed in terms of the various solute-solvent interactions that are reflected by the coefficients of the various terms. These are cavity effects and dispersion forces ( l), dipole-dipole and dipole-induced-dipole interactions ( s), and hydrogen-bonding between solute acid and polymer base ( a) or between solute base and polymer acid ( b). For non-dipolar solutes in all non-aqueous solvent phases, and for weakly dipolar solutes in weakly dipolar phases, the general equation reduces to a more specific equation that includes only the term due to cavity effects and dispersion forces SP=SP 0+l log L 16