Novel Methods of Studying Polymer Surfaces by Employing Contact Angle Goniometry

Abstract

Highly sophisticated instrumentations are available today for studying solid polymeric surfaces. Nevertheless, the relatively modest technique of contact angle goniometry has a disproportionately high potential for providing information on surface energetics and surface transformation that are largely unexploited. Such techniques employing one- and twocondensed-phase contact angle measurements are especially useful for studying the interfacial properties of polymeric surfaces, both electrically charged and neutral, that exhibit variability in surface composition and thus in surface properties, due to segmental mobility. Plasma-treated polymer surfaces, hydrogel surfaces, tissue and cellular interfaces are ordinarily prone to rapid and drastic surface changes depending on the polarity of the adjacent fluid phase or solid surface. Relations that have proven to be useful include adhesion tension and the relative contact angle hysteresis both as a function of the advancing contact angle. Hence, information can be obtained on surface hydrophilicity, thin film stability as related to disjoining pressure, and water-solid interfacial tension, all which play an important role in such widely diverse phenomena as the biocompatibility of contact lenses and other biomaterials, surgical trauma, tear film stability, cellular interaction, and bioadhesion.