THE EFFECT OF SURFACE HYDROGEN BONDING (ACID-BASE INTERACTION) ON THE HYDROPHOBICITY AND HYDROPHILICITY OF COPOLYMERS: VARIATION OF CONTACT ANGLES AND CELL ADHESION AND GROWTH WITH COMPOSITION

ABSTRACT

The dependence of cell or bacteria adhesion and growth on the polarity of a polymer substrate, as controlled by the composition of a HEMA-EMA copolymer, has been studied by contact angle measurements. These have been analyzed by the acid/base hydrogen bonding methodology of van Oss, et al. It was found that adhesion and growth of mouse 3T3 cells occurred on surfaces for which the acidic parameter, γ^⊕ _S, was negligibly small. This was the case above 50% EMA, for which γ^p was zero, and both attachment and growth occurred. The γ^⊕ parameter was appreciable, but approximately constant, independent of composition of the copolymer. The acid/base theory thus supplants the simple polar-nonpolar (γ^pandγ^d) hypothesisin regard to cell adhesion. A new 3-dimensional representation of hydrophilic/hydrophobic behavior is suggested, to implement the acid/base description.