Preparation And Properties Of Fouling Resistant Silicone-based Marine Antifouling Coatings

Marine biofouling profoundly influences marine industries and activities.The use of antifouling coatings that rely on the release of biocides is an effective method to inhibit biofouling.However,it has a negative impact on marine ecology.Silicone based fouling release coatings(FRCs)with low surface energy,low elastic modulus,and smooth surface weakly adhere to marine organisms.They can realize antifouling only through physical action and have attracted increasing attention due to their environmental friendliness.However,traditional silicone based FRCs have weak adhesion to substrates,poor mechanical strength,and lack of fouling resistance,limiting their wide applications.Aiming to solve these problems,we designed and prepared silicone-based coordination antifouling coating,silicone based polyurea antifouling coating and self-stratified silicone based polyurethane antifouling coating with high-adhesion in this thesis.The relationship between the surface properties,antifouling performance,and mechanical properties of these coatings and their structures and composition has been studied.The main contents are as follows:(1)The silicone based coordination antifouling coating was prepared by forming complexes between the benzimidazoly groups on poly(dimethysiloxane)(PDMS)chains and zinc ions through metal coordination,where the benzimidazoly groups were grafted onto PDMS with vinyl groups via thiol-ene click reactions.The complexes act as both reversible cross-linkers and non-leaching antifouling agents,just as the proverb says,“Kill two birds with one stone”.The surface properties,such as wettability,surface energy,and surface elastic modulus,selfhealing performance and antifouling ability of the materials were investigated through contact angle,atomic force microscopy,self-healing,anti-bacteria,and diatom adhesion tests.These results proved that the silicone coordination coating has excellent self-healing ability in air and artificial seawater under room temperature,good substrate adhesion strength,long-term underwater stability,and excellent fouling resistance performances.(2)The PDMS based polyurea with pendant vinyl groups was prepared by the condensation reaction of aminopropyl-terminated polydimethylvinylsiloxane,aminopropyl terminated polydimethylsiloxane,and isophorone diisocyanate,followed by introducing Znbenzimidazoly complexes to obtain the high strength silicone based polyurea antifouling coating.Adhesion,tensile and impact resistance tests show that the coating has excellent mechanical properties and adhesion strength attributed to a large number of hydrogen bonds and coordination bonds.The tensile strength is up to ～9 MPa,and the adhesion strength to the substrate is up to ～3 MPa.The dynamic dissociation and reconstruction of both hydrogen bonds and coordination bonds endow the coating with impact resistance.Moreover,the presence of dynamic reversible bonds makes the coating self-healing.Furthermore,the presence of nonreleasing metal ligands makes the coating excellent anti-adhesion ability to fouling organisms such as bacteria and diatoms.(3)A reactive amphiphilic polymer(RAP)with PDMS main chains terminated silanol groups and side chains containing polyethylene glycol and fluorocarbon ester was first prepared by free radical telomerization and hydrolysis polycondensation reactions.Then,RAP was introduced into silane-terminated polypropylene glycol polyurethane(s-PU)and dopamine-and silane-containing polyteramethylene glycol polyurethane(d-PU),respectively.The RAP can react with the silanes of the polyurethane to crosslink into the coating system.Attenuated total reflection infrared spectroscopy,X-ray photoelectron spectroscopy,dynamic and static contact angle,water absorption and antifouling tests show that RAP can spontaneously migrate to the surface of the coating during the film formation and endow the coating excellent antifouling ability with a low amount.Due to the presence of dopamine groups,the d-PU coating exhibits excellent adhesion strength,underwater adhesion,and bulk self-healing ability.This strategy simultaneously realized the antifouling moieties on the outer surface,high adhesion strength on the bottom,and self-healing properties on the main body.