Surface tension properties of surface-coating for application in biodiagnostics determined by contact angle measurements

摘要

For a better understanding of the adsorption behavior of biomolecules the surface tension parameters of surface-coatings for biological applications are determined by contact angle measurements. The correlation between surface tension parameters and chemical composition of thin films made of cellulose derivatives with varying functional groups and amino-functional thin films with varying backbone on glass cover slips is investigated. Calculations are based on two different theoretical methods, the Geometric mean (GM) approach according to Owens, Wendt, Rabel and Kalble and the lifshitz-van der Waals acid/base (LW/AB) approach according to van Oss, Good an Chaudhury. The values obtained for the surface tension components from the different approaches are consistent. All films investigated reduce the surface tension of the cover slip and are monopolar with strong electron-donor capabilities. While the polarity of the films varies with the choice of the functional group at the cellulose backbone, we only found a minor effect when the backbone varies. For the cellulose derivatives the degree of substitution correlates well with the electron-donor/acceptor properties.