Development of a bespoke sensory surface to combat biofouling in the maritime sector

Abstract

Biofouling is defined as the colonisation process of a solid surface (living or dead) by sessile organisms that poses a significant global industrial problem with increased drag, fuel consumption, greenhouse gas emissions and introduction of non-native species. Current biofouling management processes such as visual inspections, regulations, antifouling coatings, in-water cleaning, grooming, and dry-docking are included. Currently there is no in situ detection method available to recognise biofouling in real-time. One of the problem biofouling species is the blue mussel, Mytilus edulis, and was therefore chosen as the model organism in this study. The overall aim of the study was to develop a bespoke sensory surface to monitor in situ biofouling in real-time and demonstrating its use synergistically with a novel non-toxic antifouling technology, laser microtexturing. M. edulis were exposed to test surfaces and were compared to controls. Materials tested were PVC, Nylon 6, Silicone and PTFE with varying relative permittivities and surface energies. The sensor used was of the planar electromagnetic interdigitated electrode type. Frequency operating range on the VNA was from 10 MHz to 15 GHz, key frequencies were identified for M. edulis byssal plaque detection on the surface. Microtopographies were developed with a nanosecond pulsed fibre laser on stainless steel. Microtopographies were transferred to Silicone and antifouling and foul-release efficacy was assessed (byssal plaque area, total number of byssal plaques, adhesion strength). The presence of the microtopography demonstrated an increased plaque area with a reduced adhesion strength. The combination of sensory surface with microtopography and silicone, as an antifouling mechanism, demonstrated the detection of M. edulis in situ and in real-time. The synergistic interaction of the sensor’s EMW with the hydrophobic foul-release silicone surface and antifouling microtopography demonstrated detection of M. edulis byssal plaques as well as the specimen itself while reducing the incidence of mussel settlement overall.