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Chemistry Seminars
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October 22, 2009 |
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Michael R. Detty
University at Buffalo
Buffalo, NY
Xerogel Coatings with Antifouling and Fouling Release Properties
Marine biofouling is a worldwide problem costing billions of dollars per year in transportation costs due to increased fuel consumption from added drag. Within seconds of immersion, surfaces acquire a proteinaceous conditioning film prior to organism attachment. Within a few hours of immersion, bacteria, unicellular algae, and cyanobacteria (blue-green algae) can colonize a clean surface to form a biofilm, which on unprotected surfaces will rapidly become overgrown by macrofoulers such as barnacles, tubeworms, and macroalgae. Hybrid sol-gel-derived xerogel films prepared from a variety of aminopropylsilyl-, fluorocarbonsilyl-, and hydrocarbonsilyl-containing precursors can be designed to minimize biofouling and maximize fouling release by appropriate control of surface energy and “wettability” (water contact angles). Other xerogel films containing catalysts for the activation of hydrogen peroxide minimize biofouling through the production of “bleach” on the coating surface from naturally occurring reagents in the sea. Both of these approaches obviate the use of “heavy metals” such as tin and copper, which have been used for the prevention of biofouling, but which leach into the aquatic environment and are toxic.
