Engineering Graphene Oxide based Nanocomposite Paints against Marine Biofouling

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Marine biofouling, the accumulation and colonization of various marine microorganisms, plants, algae, and shellfish on vessels' hull exposed to seawater, generates significant problems for marine shipping1. For example, biofouling based frictional effects results in decreased speeds and up to 40% increased fuel consumption to compensate; as a result, the International Maritime Organization (2009) estimates that greenhouse emissions (CO2 and SO2) would be expected to increase 38-72% by 2020 if no new efficient technology is developed. Currently, many antifouling technologies and paints have been developed to address the issue; however, if environmentally benign such as silicone elastomers, they are less effective and unsuitable for stationary or slowing moving vessels. Current effective anti-fouling agents are associated with adverse and often non-specific toxicity through their release of heavy metals (copper, tin or zinc) which in some cases such a tributyltin, disrupted endocrine systems of non-target organisms. Consequently, it is highly desirable to develop efficient and environmental friendly approaches to address marine biofouling. Graphene, the single atomic layer of graphite, possesses many extraordinary properties such as super high electrical, thermal conductance and mechanical properties. Recently, it was found that graphene oxide (GO), graphene sheets derivatized with carbonyl, epoxy, and hydroxyl groups, have intrinsic bactericidal properties6. In my group, recently we found the presence of NaCl could significantly increase the amount of hydroxyl radicals generated with a small amount of H2O2, namely, enhancing bactericidal effects of GO. When nanocomposite materials are combined, the unique properties contributed by each constituent (i.e., high bactericidal effect from GO, self-cleaning properties from CuO NPs, and catalytic efficiency properties from layered double hydroxides (LDHs)), the bactericidal effect can be synergistically enhanced when GO is produced as a composite with other nanomaterials, such as ZnO and silver nanoparticles7, in the presence of high concentration of chloride as in sea water. Consequently, we hypothesize that GO, structured as a composite with other nanozymes, may be an effective candidate for formulating anti-biofouling paints for marine vessels. With the huge surface area and negligible weight of GO, the paint could be effective in industrial and recreational shipping applications. The objective of the proposed project is to test the feasibility of using such nanocomposite materials to prevent marine fouling.