CORRELATION BETWEEN LEWIS ACID-BASE SURFACE INTERACTION COMPONENTS AND LINEAR SOLVATION ENERGY RELATIONSHIP SOLVATOCHROMIC ALPHA-PARAMETER AND BETA-PARAMETER

In this paper, we report our unexpected finding about the correlation between Lewis acid-base surface interaction components and linear solv ation energy relationship (LSER) solvatochromic parameters alpha and b eta. In 1987, van Oss, Chaudhury, and Good proposed to split the asymm etric acid-base parts of a bipolar system into separate surface tensio n components: Lewis acid (electron acceptor) gamma(+) and Lewis base ( electron donor) gamma(-). It was assumed that the ratio of gamma(+) an d gamma(-) for water at 20 degrees C was to be 1.0. With that ratio as a reference, the base components, gamma(-) for other liquids, biopoly mers, polymers, and solids appeared to be overestimated. Recently, we unexpectedly found a correlation for liquids between gamma(+) and gamm a(-), and a (solvent hydrogen-bond-donating ability) and beta (solvent hydrogen-bond-accepting ability) introduced since 1976 by Taft and Ka mlet. From that correlation, we obtained a more realistic ratio for th e normalized alpha and beta values for water at ambient temperature to be 1.8 instead of 1.0. Based on this new ratio, we calculated total s urface tensions for related materials at 20 degrees C. They are genera lly unchanged as expected, despite the considerable, favorable change in the gamma(+) and gamma(-) values in the direction of lowering the L ewis basicity. The predicability of solubility with interfacial tensio n is also unaffected. For example, the sign of those negative interfac ial tensions that favor solubility remains the same. In addition, the implications of other LSER parameters, e.g. Pi and delta(H)(2), on su rface properties will be briefly mentioned.