MEASURING SURFACE HYDROPHOBICITY AS COMPARED TO MEASURING A HYDROPHOBIC EFFECT ON ADHESION EVENTS

Simple contact-angle methods are commonly used to describe surface inf luences on phenomena including adsorption, adhesion, fouling, and clea ning. However, for the purpose of quantitatively relating surface hydr ophobicity to such phenomena, contact-angle analysis may be insufficie nt. Here we show that even with model hydrophobic and hydrophilic surf aces, measurement of the effect of surface hydrophobicity on adsorptio n of the antimicrobial proteins nisin and bacteriophage T4 lysozyme yi elded conflicting results, apparently because different mechanisms gov ern events at the interface, depending on surface hydrophobicity. This finding is explained in terms of the presence of two competing mechan isms for attractive associations at these surfaces: hydrophobic and at tractive electrostatic associations.