Engineering Graphene Oxide based Nanocomposite Paints against Marine Biofouling

海洋生物污损，即各种海洋微生物、植物、藻类和贝类在暴露于海水的船舶船体上的积累和定殖，对海洋运输产生重大问题1。例如，基于生物污垢的摩擦效应导致速度降低，并增加高达40%的燃料消耗来补偿;因此，国际海事组织（2009年）估计，如果不开发新的高效技术，到2020年，温室气体排放（CO2和SO2）预计将增加38-72%。目前，已经开发了许多防腐蚀技术和涂料来解决这个问题;但是，如果环境友好，如有机硅弹性体，它们的效果较差，不适合静止或缓慢移动的船只。目前有效的防污剂通过释放重金属（铜、锡或锌）而具有不利的且通常是非特异性的毒性，在某些情况下，重金属如三丁基锡会破坏非目标生物的内分泌系统。因此，非常需要开发有效且环境友好的方法来解决海洋生物污损。 石墨烯是石墨的单原子层，具有超高的导电性、导热性和机械性能等优异性能。最近，人们发现氧化石墨烯（GO），用羰基、环氧基和羟基衍生的石墨烯片，具有固有的杀菌特性6。在我的小组中，最近我们发现NaCl的存在可以显著增加用少量H2 O2产生的羟基自由基的量，即增强GO的杀菌效果。当将纳米复合材料组合时，每种成分贡献的独特性质（即，来自GO的高杀菌效果、来自CuO NP的自清洁性能和来自层状双氢氧化物（LDH）的催化效率性能），当GO作为与其它纳米材料（例如ZnO和银纳米颗粒7）的复合物在如海水中的高浓度氯化物的存在下产生时，杀菌效果可以协同增强。因此，我们假设GO与其他纳米酶的复合结构可能是用于制定海洋船舶抗生物污损涂料的有效候选物。由于GO具有巨大的表面积和可忽略的重量，该涂料在工业和娱乐航运应用中可能是有效的。拟议项目的目的是测试使用这种纳米复合材料防止海洋污染的可行性。

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.