Using encrusting bryozoan adhesion to evaluate the efficacy of fouling-release marine coatings

Biofouling communities are spatiotemporally diverse, underscoring the need to assess fouling-release (FR) coating performance against common biofouling taxa at multiple field sites. Adhesion strength assessments of FR coatings incorporate few taxa into standardized protocols. This study tested the feasibility of incorporating existing ASTM barnacle protocols on tubeworms and encrusting bryozoans (EB). Additionally, trends in adhesion strength among these taxa were compared at two field sites. EB adhesion at both field sites showed consistent results and adhesion strength followed the same trend: tubeworms > barnacles >EB. Testing EB adhesion was feasible and enhanced assessments of FR coatings by increasing the diversity of assessed taxa.

Evaluation of the performance enhancement of silicone biofouling-release coatings by oil incorporation

In response to increased evidence of ecosystem damage by toxic antifouling paints, many researchers have developed nontoxic silicone fouling release coatings. The fouling release capability of these Systems may be improved by adding nonbonding silicone oils to the coating matrix. This idea has been tested by comparing the adhesion strength of hard- and soft-fouling organisms on a cured polydimethylsilicone (PDMS) network to that of the same network containing free polydi-methyldiphenylsilicone (PDMDPS) oil at five exposure sites in North America and Hawaii. Fouling coverage is discussed, together with the bioadhesion data, to emphasize that although these coatings foul the fouling is easily removed. The partitioning of the incorporated oil upon exposure of the coatings to a simulated marine environment containing sediment was determined. Less than 1.1 wt% of the incorporated oil was lost from the coating over one year, and the toxicity of these coatings was shown to be minimal to shrimp and fish. Brush abrasion wear was greater for coatings containing free oil, but the modulus of elasticity was not appreciably decreased by the addition of 10wt% free oil.