Preparation Of Microcapsules And Its Study On Bionic Anti-Fouling Performance Applied To Coatings

Marine bio-fouling is a worldwide problem in marine systems,such as marine ships,submarines and underwater pipelines,which caused a great economic waste,and severely restricts the development of marine affairs.With the deepening of marine,the research on environment-friendly antifouling coatings is very important and extremely urgent.The traditional antifouling paints which usually contain organic tin,cuprous oxide or other toxic substances,will gradually withdraw from the stage of history for their high toxicity,the anti-fouling paints are developing toward the absence of organic tin,low cuprous oxide,low heavy metal bactericides and non-toxic antifoulant.Therefore,the development of environmentally friendly,non-toxic anti-fouling paints material is imminent.The bionic microstructure type,mucus effusion type,antifouling agent release type,three types of antifouling paints were built basing on the perspective of bionic,mainly from the perspective the surface microstructure,antifouling agent release,and mucus effusion.This article developed two new nontoxic-releasing antifouling coatings,and the antifouling performance of the coatings was evaluated by means of microstructural characterization and surface performance testing of the system,combined with the laboratory simulation of microbial adhesion experiments and the real sea peg board testing.(1)Antifouling coating containing silicone oil microcapsules.The silicone oil microcapsule was obtained by the polymerization of urea and formaldehyde under the action of surfactants,and water as the disperse phase,ammonium chloride and resorcinol as cross-linking agents and curing agents.The prepared microcapsules as antifoulant were embedded into the zine acrylate resin.The addition of silicone oil microcapsules has successfully built an antifouling coating combining bionic microstructure with mucus leakage.The effects of the types of the surfactant,stirring speed,heating rate and core shell ratio on the microcapsule morphology were detailedly discussed,and then optimal synthesis is obtained.IR,TG/DTG and SEM were utilized to characterize the structure and morphology of the microcapsules,and changes of parameters such as surface contact angle,SEM were used to analyze the reasons of its antifouling effect and explore its antifouling mechanism.And the antifouling performance of the antifouling coatings were explored by the artificial simulation tests and real-sea tests of samples.Results of antifouling test show that the silicone oil microcapsule antifouling coating forms a micro-nanostructure on the coating surface which highly semblable to the microstructure of the lotus surface,which greatly reduces the surface energy of the coating and makes the hydrophobic properties enhanced.The evaluation of the antifouling performance shows that the microstructure and the sustained release of silicone oils have led to a good antibacterial inhibition effect at the initial stage.However,the results of real-sea tests indicate that the antifouling property will be weakened if the coatings are immersed in the ocean for a long period of time.(2)Antifouling coating containing capsaicin microcapsules.Inspired by the basic and results of the first coatings,capsaicin microcapsule was designed and prepared as an antifoulant,xylene was used as a solvent,urea-formaldehyde resin was used as a sustained-release carrier material,to obtain a kind of microsphere embedding of silicone oil and capsaicin.The prepared microcapsules as antifoulant were embedded into the zine acrylate resin.Capsaicin and silicone oil were co-coated in microcapsules to construct an anti-fouling coating combining biomimetic microstructure,mucus exudation,and bio-foulant anti-foulant.The effects of temperature,stirring speed,and the different molecular weight of polyvinyl alcohol on the microcapsules were studied.The physicochemical properties of the microcapsules were studied by means of TEM,SEM,FTIR,TG/DTG and contact angle changes.Using laboratory simulations combined with real sea peg experiments,the antifouling performance of the biomimetic antifouling coating was investigated and good antifouling effect was demonstrated.The experimental results show that the addition of capsaicin makes the coating exhibit better antifouling performance than the silicone oil microcapsule coating,indicating that the synergistic effect of microstructure,mucilage exudation,and antifouling agent can bring about better antifouling performance.