SOME REFLECTIONS ON ACID-BASE SOLID-SURFACE FREE-ENERGY THEORIES

This paper considers the correctness of the application of Good-van Os s theory (vOGT) to the calculation of acid-base components of solid su rface free energies. Theory equations are written in a matrix form, an d their application is analyzed particularly from a mathematical point of view. A calculation procedure similar to the approach used for oth er scales of acid-base strength is suggested to obtain in a straightfo rward manner the necessary material coefficients. The chemical consequ ences of these considerations are also discussed. The acceptability of current experimental literature data and the validity of the calculat ions obtained from them by the proposed method are considered, showing the origin of some inconsistencies in current results. Some general c onsiderations regarding the difficulties commonly encountered in the a pplication of vOGT are also discussed, and it is shown that they can b e rationalized or eliminated with more acid solvents being included in the solvent set and the properties of the reference solvent being cor rectly chosen. The difficulties encountered in correctly expressing th e acid properties of some polymers are closely examined. Finally, some indications are given of the future possible developments of vOGT. (C ) 1997 Academic Press.