Design And Preparation Of Inert Materials For Marine Fouling Organisms Attachment

Since the metal-based antifouling compounds in traditional antifouling coatingscould bring about irreversible harmful influence on the marine environment, thus it isnecessary to develop environmentally friendly antifouling materials. It was wellknown that marine organisms selected the surface on which they could get thestrongest attachment strength to settle, or they would go away and find other surface.Therefore, if there were some materials which could not form enough attachmentstrength with fouling organisms, then the fouling organism would be unwilling tosettle onto them. This was the purpose of this dissertation, and it was expected todesign an inert materials for marine fouling organisms attachment through the studyon how those physical, chemical as well as microtopographical materialscharacteristics influence the fouling behavior of marine organisms, the preparation ofthis materials was alo studied. The conclusions were as follows:(1) Different marine organisms showed different fouling behavior onmaterials with various surface energy. The results showed that with the surface energydecreasing, the attachment strength would become higher and higher for diatoms,however it would become lower and lower for ulva spores. It was also concluded thatthe surface energy could influence the wetting area of fouling organism adhesives,and since wetting area was a very important factor for them to get enough attachmentstrength, therefore it could finally influence the attachment of marine organisms tosome extent. It was well known that there were thousands of fouling organisms inmarine environment, and some of them attached with hydrophobic adhesives whileothers with hydrophilic ones, therefore it was impossible to inhibit the attachment ofall fouling organisms only depending on the design of surface energy features.(2) Different marine organisms showed the same fouling behavior onmaterials with various elastic modulus(E). The results indicted that all the staticattachement number of both diatoms and ulva spores were not influenced by thevariation of materials elastic modulus while it could bring about significant change fortheir detachment percentage under the dynamic water flow, and the detachmentpercentage of both diatoms and ulva spores could become higher and higher with theelastic modulus decreasing in a linear relationship with E1/2. It was also concluded thatlower elastic modulus could make materials surface easier to be deformed into shrinkles, then the attachment area of fouling organism would decrease and the watershear stress concentration appeared, therefore the critical water shear stress necessaryto make fouling organisms deattach would become lower and the deattachmentpercentage could be significantly improved.(3) Packing density of zwitteric ion molecule assembled on the materialsurface had no influence on the static inhibition efficiency as well as deattachmentpercentage under dynamic water flow for all tested fouling organisms. The results alsoshowed that with the increasing of chain length of zwitteric ion molecule ofPolySBMA, the inhibition efficiency would increase for all fouling organisms, and thedeattachment percentage would also increase after a first short decreasing period. Itwas concluded that both the hydrated film formed by the assemble molecule of PolySBMA on the surface and the space barrier effect of PolySBMA chain could inhibitthe attachment of fouling organisms and improve their deattachement percentageunder dynamic water flow.(4) All of the parameters of microtopography could affect the attachementbehavior of fouling organisms, and a TPW model was set up based on antifoulingresults of various geometric parameters. It was found that TPW and the inhibitionefficiency(Y%) was in relationship as the following: Y%=（60.92-14.6ln(TPW)）×100%. When TPW increased, the inhibition efficiency would decrease, while whenit decreased, the inhibition efficiency would increase. It was concluded that TPWinfluenced the fouling organism behavior with varying their attachment area on thematerials surface. The lower the TPW, the lower the attachment area, and theattachment strength the fouling organisms could get would be lower, then it would bemore difficult to attach firmly and easier to deattach from the surface for them.(5) Based on the study of synergistic effect on marine organisms foulingbehavior of various material characteristics, such as surface energy, elasticmodulus(E), chain length of assembled PolySBMA(n) as well as microtopography(TPW), it was found that they were in relationship with inhibition efficiency(Y%)and deattachment percentage(T%) for all tested fouling organisms as follows: Y%=（81.5-9.40TPW-0.266E+0.0138n）×100%，T%=（82.3-4.60TPW-14.1E1/2+0.0614n）×100%According to the above function, the necessary material characteristics couldbe built and calculated to satisfy the demand of inhibition as well as deattachment formarine fouling organisms.(6) A chemical approach to control the TPW of microtopography was set upwith the combination of molecule self-assembly and particle dissolution. With this this channel and based on PDMS, the material with combined characteristics ofcertain elastic modulus(E), chain length of assembled PolySBMA(n) as well asmicrotopography (TPW) was prepared. Test results showed all the designedcharacteristics were achieved and accurately controlled, the requirement of staticinhibition efficiency and deattachment percentage under dynamic water flow was alsosatisfied, the deviation between their measurement value and designed value wasrespectively0.5%and1.3%.