Antifouling Protection of Surfaces Immersed in Marine Environment by Natural Surfactants as Bioactive Contained in Coating Based on Natural Resin

Abstract

Surface biofouling of materials immersed in the marine environment is a problem that particularly affects maritime industries and equipment. The biological community present in these environments develops on the immersed surfaces of different structures, causing economic damages to the local facilities. Antifouling coatings based on synthetic chemicals, while being the primary strategy used to combat fouling in the marine industry, are detrimental to other ecosystem beings in addition to target organisms (biofouling). To avoid or reduce this biofouling, a non-biocidal strategy is the application of coatings based on natural surfactants, making them more hydrophobic, imposing it difficult to fix biofouling. In this context, the aim of the present study was to formulate a non-biocidal antifouling coating containing natural surfactants, obtained by fermentation process and/or by chemical modification of residual soybean oil, evaluating its antifouling effect on local marine biofouling. To this end, a natural resin-based matrix containing the natural surfactants was prepared, which was applied to metal panels and after curing the coating, these were followed for immersion tests at the Port of Recife-PE, Brazil for 25 days. After this period, the panels were photographed and analysed for the macrofouling biota present. There was a reduction in biofouling around 30% compared to untreated panel. After immersion tests at the Port of Recife-PE and analysis of the covered area, the panel coated by the matrix + laurate and matrix + hydroxylated acid exhibited the best antifouling activity during the period tested. The results of the embedded area, through the ImageJ software, demonstrated the promising effect of the antifouling coating in the field, evaluated in the treatments in relation to the negative control, evidencing the great biotechnological potential of natural surfactants in the treatment of the biofouling.