Preparation And Antifouling Performance Of Modified Polydimethylsiloxane And Flocking Material

Marine biofouling leads to problems such as increased shipping costs and corrosion.Applying antifouling coatings is one of the most economical and effective ways to inhibit biofouling.At present,marine antifouling coatings mainly rely on the release of heavy metal biocides to kill fouling organisms to resistant biofouling.But such biocides can also cause pollution to the marine environment.So,the development of biocide-free antifouling coatings has become hot issues.In this paper,slippery liquid-infused porous surfaces(SLIPS)PDMS,hydrophilic PDMS,SLIPS flocking materials and zwitterionic flocking materials were prepared by modifying polydimethylsiloxane(PDMS)and flocking materials through lubricating oil infusion,surface chemical modification,surface coating modification,etc.,respectively.The antifouling performance of the material was evaluated by the antifouling performance test both in the laboratory and the real sea environment.Several comparative experiments were designed to study the influence of the surface morphology and wettability of the material on the antifouling performance.A polysilicon methoxy curing agent was synthesized by the amino-epoxy ring-opening reaction.A highly cross-linked modified PDMS(MPDMS)was prepared by the dealcoholization condensation reaction between hydroxyl-terminated polydimethylsiloxane and the agent.The SLIPS antifouling material with a dimethyl silicone oil layer and the SLIPS antifouling material with a poly-α-olefin(PAO)layer were respectively prepared by the swelling method and the physical blending method.Through comparative experiments,the effect of lubricant type,addition method and addition amount on the surface lubricant layer of the material was studied,and it was found that it was found that silicone oil with good compatibility with MPDMS can only form a lubricant layer on the surface of the SLIPS coating prepared by the swelling method;while the PAO with poor compatibility with MPDMS can only form a lubricant layer on the surface of the SLIPS coating prepared by the physical blending method.Diatom attachment experiments in aboratory show that lubricant layer can improve antifouling performance.Compared with PDMS,the inhibition rate of diatom adhesion of the silicone oil swollen MPDMS SLIPS material and the PAO blended MPDMS SLIPS material were 99.3%and 94.9%,respectively.The difference in the inhibition rate of the two diatoms is attributed to that silicone oil has a higher compatibility for MPDMS than PAO,which makes lubricant layer more difficult to be replaced by diatoms.Flame treatment was used to modify the surface of PDMS,so that the chemically inert methyl groups on the surface of PDMS are converted into active silanol groups.Zwitterionic silane-modified PDMS(Z-PDMS),fluorosilane-modified PDMS(F-PDMS)and PVA/boric acid-modified PDMS(PVA-P)antifouling materials were prepared based on the silanol on the surface of PDMS.It was also found that flame treatment can cause wrinkles on the PDMS surface.The generation and orientation of wrinkles depend on the thermal deformation of the material.The size of wrinkles increases with the flame treatment time.PDMS without thermal deformation has no wrinkles on the surface after flame treatment.The size of the wrinkles on the surface of the sample that can be thermally deformed increases with the extension of the flame treatment time.Comparing the adhesion of diatoms on the surface of samples with different morphologies,the results show that the larger the fold size,the higher the amount of diatom adhesion.The adhesion amount of diatoms on the surface of F-PDMS,Z-PDMS and PVA-P materials with different morphologies was also investigated,and it was found that for the same modification method,the amount of diatom adhesion on the smoothest material was the least.In the case of the same morphology,the inhibition rate of hydrophilic modified Z-PDMS and PVA-P diatoms is 99%and 86%,respectively,compared with PDMS,which is better than the 50%inhibition rate of hydrophobic modified F-PDMS.Among them,PVA-P can effectively reduce the adhesion of fouling organisms,especially mussels in the field anti-fouling performance test.In this research,hydrophobic electrostatic flocking surface(H-EFS)materials were prepared by electrostatic flocking technique combined with drop-coating.Scanning electron microscope(SEM)characterization shows that PDMS modified layer only covers the top surface of flocking fibre and leave interfiber unfilled.SLIPS electrostatic flocking surface(S-EFS)antifouling material was prepared by filling dimethicone into the interfiber of H-EFS.Research on the effect of flocking time on fibre density and dimethicone storage shows that a45 s flocking time results in the highest fibre density of 87.3 g/m~2 and dimethicone storage of195.4 g/m~2.The surface dimethicone exhibits great stability after 30 days of immersion in artificial seawater.The antifouling performance evaluation results in the laboratory and the real sea environment show that,compared with the blank control sample and H-EFS,S-EFS can effectively inhibit the attachment of barnacles,tube worms,tunicates and bryozoans.Quantitative real-time polymerase chain reaction was used to test the mussel key adhesion protein(Mfps)gene expression level on the surface of S-EFS,H-EFS and PDMS.It was found that the Mfps-related gene expression level on the surface of S-EFS was the highest.EFS is second,PDMS is the lowest,which demonstrate that the attachment inhibition of S-EFS and H-EFS is not achieved by inhibiting Mfps protein excretion.Comparing mussel attachment on PDMS,H-EFS,PDMS coated foam to investigate the morphology effect,porosity on the surface of the material was found inhibiting the mussel attachment.Dopamine simulation Mfps attachment experiment demonstrates that the lower surface energy between dimethicone and PDMS can prevent dopamine sedimentation on PDMS surface,which explains why dimethicone can reduce Mfps attachment.Electrostatic flocking material(EFS)was modified by in-situ polymerization to obtain zwitterionized flocking material(ZEFS).The fibers on the surface of the material are bonded into clusters by the modified layer of polymethacrylate sulfobetaine(PSBMA),but the upright state of the fibers and the voids between the fibers are still retained.The anti-mussel and diatom performance of ZEFS was evaluated in the laboratory.In the anti-mussel test,the number of plaques on the glass,PDMS,and EFS control samples averaged 293,93 and 21,while the number on the ZEFS surface was only 4.In the anti-diatom test,there is no diatom attachment on the fibers surface of EFS and ZEFS,but a large number of diatoms are attached to the nylon plate with the same fiber material,indicating that the fine fibrous surface morphology can resist the attachment of diatoms.The antifouling performance of ZEFS was evaluated in field.Compared with the blank control and EFS,ZEFS can effectively reduce the attachment of barnacles,tube worms,tunicates and bryozoans.The results show that the PSBMA modified layer can effectively improve the antifouling performance.In order to understand the influence of surface fiber posture on mussel adhesion,the adhesion of mussels on the surface of ZEFS with upright fibers and the same PSBMA modified lodging fiber material was compared.It was found that the upright fibers can effectively inhibit mussel adhesion.