ON THE EVALUATION OF SURFACE INTERACTIONS BY INVERSE GAS-CHROMATOGRAPHY

This paper examines the applicability of inverse gas chromatography (IGC) to the quantification for polymer substrates of electron acceptor-donor (or Lewis acid-base) interactions. Polycarbonate is used as the reference stationary-phase material. Various options have been compared for the graphical representation of experimental data leading to the evaluation of acid-base contributions, and preference among these was accorded on the basis of the convenience and breadth of applicability. From the temperature dependence of these acid-base contributions, the enthalpies of acid-base interaction have been determined. These were found to correlate with donor and new acceptor numbers, both in thermodynamically consistent units. Parameters expressing the ability of the polycarbonate surface to accept or to donate electrons may now be compared on an unequivocal basis. The polymer may be described as being amphoteric but with predominant basicity.