Antifouling Performances Of Textured Silicone Modified Coatings

Marine biofouling caused enormous harm to ships and other sea facilities.Usually,the marine biofouling can be reduced remarkably via painting antifouling coatings.With the improvement of environmental protection consciousness,development of green non-toxic anti-fouling coatings is the future development trend for marine antifouling technology.Many natural creatures(such as shark,whale and lotus leaf)show excellent antifouling performances and self-cleaning properties which are due to their surfaces owning special micro/nano binary textures.Inspired by this interesting phenomenon,building micro/nano-textures on the coating surface may be a good idea to improve coating’s anti-fouling performance.The siloxane modified acrylic resin coatings with different bionic textures were fabricated by mimicking the microstructures of taro leaves,rose petals and sharkskin via a replication method.The physical and chemical properties of the as-prepared coatings were systematically characterized by FTIR spectroscopy,SEM,AFM and contact angle measurements.Moreover,the antifouling properties of the bionic textured coatings against algae(N.closterium,P.tricornutum and Chlorella)were investigated.The results indicated that there are massive scales on the bionic textured coatings with sharkskin morphology,and the coatings performed good antifouling performances and can reduce the amount of N.closterium,P.tricornutum and Chlorella by 53%,42% and 73%,respectively.The antifouling mechanism of the sharkskin is called the “cascade structure effect ".The bionic textured coatings with taro leaves and rose petals morphology showed a poor antifouling performance because the algae preferred to settle in the edge area which encouraged the algae settlement.This phenomenon is called the “edge effect”.Regular micro/nano-pillar textures with different diameter and distance on bionic coatings were also successfully prepared through the replication method.The physical and chemical properties of coatings were systematically characterized,and the influences of texture geometry on the antifouling properties of bionic coatings were investigated.The results showed that the algae tend to “bridge” among pillars when the texture size(pillar diameter and distance)was smaller than algae size for the regular textured coatings with pillars.And on this occasion,the amount of algae will be reduced and the reduction ratios of N.closterium,P.tricornutum and Chlorella could reach 52%,59% and 33% under the best conditions.But the algae attached to the surface in the form of “mosaic” which can increase the algae attachment when the texture size(pillar diameter and distance)was larger than algae size.For the regular textured coatings with pits,algae have to “across” the pit so that part of the algae body will be “suspended” and the “air cushion” will be formed between the pit and algae when the pit diameter is smaller than algae size.On this occasion,the amount of algae will be reduced and the reduction ratios of N.closterium,P.tricornutum and Chlorella could reach 52%,47% and 31% under the best conditions.When the pit diameter is larger than algae size,algae preferred to settle in the pits and the amount of algae will be increased.Similarly,a series of textured surfaces were fabricated by mimicking the microstructures of abrasive paper via the replication method.The antifouling properties of the textured coatings were investigated.The results indicated that there are many micro-particles on the surface of abrasive paper.The textured coatings with 5000-grit abrasive papers morphology showed the best antifouling performance and the reduction ratios of N.closterium,P.tricornutum and Chlorella can reach 49%,75% and 81%.The textured coatings with 7000-grit abrasive papers morphology can reduce the amount of N.closterium and P.tricornutum by 29% and 57%,respectively.But it can’t inhibit the settlement of Chlorella.