No abstract

BACKGROUND: UV-curable coatings are promising candidates for environmentally friendly marine foulingrelease coatings. Cationic UV-curable epoxy-siloxane release coatings show good release performance but suffer from poor coating mechanical properties. A difunctional oxetane monomer, DOX, was co-photopolymerized with an epoxy-siloxane oligomer at loading levels from 10 to 40 wt% to obtain toughened fouling-release coatings. RESULTS:The DOX-toughened coatings showed enhanced cationic photopolymerization activity, solvent resistance and modulus. DOX-toughened coatings (10 and 20 wt%) exhibited higher impact resistance. The DOX-toughened coatings showed no leachate toxicity and the coatings were hydrophobic and non-toxic to biofilm growth when analyzed with marine bacteria and algae. In general, 10 and 20 wt% DOX-toughened coatings exhibited better marine bacteria and algae fouling-release performance among the DOX-toughened coatings. Pseudo-barnacle shear release stress for the DOX-toughened coatings increased with increasing DOX content. Live barnacle reattachment assay showed that 10 and 20 wt% DOX-toughened coatings had comparable barnacle removal stress to commercial silicone reference coatings. CONCLUSIONS: DOX-toughened (10 and 20 wt%) UV-curable epoxy-siloxane coatings exhibited enhanced mechanical properties and better overall marine fouling-release performance among the toughened UV-curable release coatings studied.

Cationic, UV -curable coatings containing the tethered biocide, triclosan, were produced and their antimicrobial activity toward Staphylococcus epidermidis and Escherichia coli determined. Two polysiloxanes functionalized with both cycloaliphatic epoxy and triclosan were synthesized using hydrosilylation. The functionalized polysiloxanes, with varied concentration of pendant triclosan, were used to produce UV-curable coatings with reasonably good coating properties. Fourier transform (FT)-Raman spectroscopy showed that the tethered triclosan moieties self-concentrate on the coating surface. Using biological assays, it was determined that the coatings possessed nearly 100% antimicrobial activity toward the Gram-positive bacterium, S. epidermidis, without leaching toxic components. For the Gram-negative bacterium, E. coli, 60-80% reduction in biofilm retention was observed for all the coatings. Interestingly, the coatings were lesser effective in reducing E. coli cell viability suggesting that the tethered triclosan were able to substantially reduce the production of the biofilm extracellular matrix with minimal adverse affect on the bacterial cells attached to the coating surfaces. The high specificity of the coatings toward S. epidermidis indicates that a novel mode of contact-active antimicrobial activity was achieved through the disruption of processes unique to the Gram-positive cell wall. These novel UV-curable coatings have potential applications in inhibiting implantable biomedical device associated infections.

Preparation and Antimicrobial Activity of 2‐Phenyl‐2‐(2′‐hydroxy‐/3′‐5′‐dichlorophenyl H‐N‐amino‐sulphophenyl/4‐methyl pyrimidyl/‐4,6‐dimethylpyrimidyl/3‐(N′‐ 2‐thiazolyl sulphanilamido)‐carboxy‐methyl‐4‐thiazolidinones and Their Benzoyl Derivatives.

To develop a cationic UV curable, tough fouling-release coating for marine vessels, a difunctional oxetane monomer was used to copolymerize with the epoxy-siloxane oligomer at loading levels from 10% to 40% wt.. The resulting coatings showed enhanced solvent resistance, impact resistance and modulus, while remained hydrophobic before and after immersion in artificial sea water. In marine microorganism bioassay, these oxetane toughened coatings showed no leachate toxicity and the coating surfaces were non-toxic to biofilm growth. The fouling removal performance for these coatings was found to be microorganism dependent. Live barnacle reattachment assay showed that the toughened coatings had a removal force comparable to the reference silicone coatings Dow Corning T2 and 3140.