Techniques for the measurement of natural product incorporation into an antifouling coating

•Natural product incorporation directly into an antifouling coating.•Electrochemical impedance spectroscopy showed higher water uptake within modified coating.•Use of non-destructive techniques to assess coating functionality.

The control of biofouling can be achieved by a variety of methods but for an open system, such as a ship's hull, a protective paint coating is the most adopted method. The incorporation of a natural product extract directly into a coating has received little previous attention. This study has investigated a combination of the antifouling compound (a natural product extract) and the delivery system (control depletion polymer) investigated together. It was necessary to investigate the natural product incorporation into a coating and finally assess the antifouling system including the primer layers in the natural marine environment. Natural products must first be practical as antifoulants to be developed further into a functional system by their incorporation into surfaces or coatings. To demonstrate this, the natural product under investigation was homogenised into a blank proprietary antifouling paint system binder, applied to primed and un-primed ship grade steel and immersed in marine environments. Electrochemical techniques were used to investigate the effects of natural product incorporation into a coating. In addition, optical and scanning electron microscopes were used to assess the physical characteristics of the coating system. The most rigorous test for an antifouling system is a field trial. Field trials were completed at a raft exposure facility, in estuarine dock conditions at the Empress dock, National Oceanography Centre, Southampton, UK.