Bionic Antifouling Functional Surface Design Based On Static Antifouling Strategy Of Sarcophyton Trocheliophorum

Marine biofouling is the attachment of organisms in the ocean to various surfaces immersed in seawater.Microorganisms gather and grow to form large fouling biological communities.This will cause damage to underwater facilities.Marine biofouling can bring about a series of environmental and social problems.For example,it increases the fuel consumption of ships and the corrosion rate of the hull.It will cause serious economic losses.Marine biofouling restricts the development and utilization of the ocean.Therefore,how to prevent biofouling has become a global issue.With people's exploration and research on antifouling methods,the bionic antifouling technology based on imitating biological antifouling strategies has gradually attracted the attention of researchers around the world for its environment friendly,broad-spectrum,and long-lasting characteristics.Sarcophyton trocheliophorum grow sessile on submarine platforms or slopes,lack an escape mechanism for fouling organisms.However,it has no fouling organisms attached to its surface,indicating that it has evolved an antifouling strategy that is different from the high-speed movement to get rid of fouling organisms.This article takes Sarcophyton trocheliophorum(call coral for short)as the research object and studies its static antifouling strategy.Carry out the design work of the static bionic antifouling functional surface.Through a series of tests on living corals(observation test,coral mucus and coral body antifouling performance test),it is found that the surface of the crown of living corals always show a stable mucus gel layer-porous structure.After the mucus gel layer disappears,the porous shape of the crown surface is blurred and the coral is corrupted which shows that the presence of the mucus gel layer can protect the porous layer.And the mucus gel layer can maintain the coral's life form.At the same time,the composition analysis of coral mucus and coral body reveals that the main organic substances in coral mucus are saccharin,gabapentin,p-toluenesulfonic acid and decanoic acid.The proportions of these organics relative to the types of compounds in which they are located are 56%,41%,68%,12%.The main organic substances in coral body is cyclic 3-(1,2-ethanediyl acetal)estra-5(10),9(11)-diene-3,17-dione,phenacetin and 4-aminobenzoic acid.The proportions of these organics relative to the types of compounds in which they are located are 11%,30%,24%.All these seven kinds of organic matter have antibacterial effects and can change the cell wall structure of P.pantotrophus and B.subtilis.This shows that corals can prevent fouling organisms from adhering by releasing these organic matters.Based on the above research,it is concluded that the static antifouling strategy of living corals is caused by the combination of the upper mucus gel layer and the lower porous layer structure and the organic antifouling components.Analyze and extract the static anti-fouling strategy information provided by corals.According to the principle of bionics similarity,design the bionic antifouling functional surface.Choose room temperature vulcanized silicone rubber(RTV-2),which is similar in elasticity to coral skin as the matrix material.Imitate the coral slime gel layer and coral body porous layer as the structural factors of the bionic antifouling functional surface.Prepare the transparent-porous structure of the upper transparent layer and the lower porous layer.7 kinds of organic antifouling components in coral mucus and body porous layer are added as the component factors of the bionic antifouling function surface.7 kinds of organic antifouling ingredients are added in six different ways for the transparent layer and the porous layer.11 kinds of bionic functional surfaces are obtained.Static and dynamic antifouling performance tests are carried out comprehensively under laboratory conditions.The results show that the prepared 11 kinds bionic functional surfaces have inhibitory effects on both P.pantotrophus and B.subtilis under static and dynamic conditions.In addition,4 kinds organic antifouling components in the coral mucus and 3 kinds organic antifouling components in the coral body are added to the transparent layer and the porous layer according to the ratio and the prepared bionic functional surface obtains the best antifouling effect.After three weeks of dynamic antifouling performance test,the bionic functional surfaces still have 69.67%and 63.54% inhibition rates on P.pantotrophus and B.subtilis.After three weeks of static anti-fouling performance test,the bionic functional surfaces still have 63.4%and 57.4% inhibition rates for P.pantotrophus and B.subtilis.This shows that the antifouling ingredient addition method that maintains a high degree of consistency with the structure of living corals can obtain the best antifouling performance.Through analysis,it is found that the long-term antifouling mechanism of the bionic functional surface is mainly the following three points: First,the characterization test shows that the bionic functional surface has low surface energy characteristics,better underwater stability,lower elastic modulus,and can slowly release antifouling ingredients in seawater.The second is that the 7 kinds of organic antifouling ingredients added in the transparent layer and the porous layer can inhibit the growth of bacteria and reduce the adhesion of fouling organisms.Third,the transparent layer can not only release antifouling ingredients,but also delay the release of antifouling ingredients in the porous layer.This transparent-porous layer structure enables the bionic functional surface to achieve a bacteriostatic rate of more than 50%during the three-week test.The test results in this article provide new ideas for the synthesis of new environment friendly and long-lasting bionic antifouling functional surfaces.Provide new ideas and insights for the antifouling of static ships.