Rapid and inexpensive quantification of the combined polar components of surface wettability: application to biofouling

A technique is presented (the SHM method) that rapidly and inexpensively quantifies surface wettability using aqueous methanol solutions. The SHM method, which can be performed using basic, generally available laboratory equipment, yields a single value that is strongly correlated with the combined polar (acid-base) components of surface wettability. In laboratory studies employing silanised glass surfaces, larval settlement rates of the bryozoan Bugula neritina and the ascidian Ascidia nigra are negatively correlated with surface wettability as quantified by SHM (r = -0.79, P < 0.02 for both B. neritina and A. nigra). In contrast, settlement of newly-metamorphosed cyprid larvae of the acorn barnacle Batanus amphitrite is positively correlated with SHM (r = +0.75, P<0.05). The SHM method is potentially useful to biologists who require initial data regarding the influence of surface wettability on biological processes before proceeding to more sophisticated, in-depth studies involving collaboration with surface chemists.