Halloysite nanotubes as nano-carriers for the development of bioinspired antifouling hybrid composites

Marine biofouling is an age-old problem with a broad impact in many marine activities, representing a major economic, environmental and health concern. Nowadays, the development of environmentally friendly and long-term solutions is a huge challenge in the maritime industry. Overall, marine biofouling is affected by different parameters, including the wettability of the surface, the roughness, the electrostatic interactions, and the use of anti-adhesive/anti-fouling molecules.1 The use of bioinspired compounds with highly efficient antifouling activity is a particularly interesting strategy for the development of eco-sustainable solutions to be used in the marine environment. At the same time, the use of nano-carriers could allow for the slow delivery of these active molecules, enabling the use of very small amounts of antifoulants while aiming at long-lasting performances.2 Here halloysite clay nanotubes, natural biocompatible and economic materials, were used as nano-containers for the entrapment and release of newly synthesised, non-toxic and nature-inspired flavonoid derivatives, already proven to be effective to prevent marine biofouling.3-4 By adjusting the dispersion of the nanotubes in a commercial epoxy paint to be used on the surface of ships hulls, we developed an homogeneous antifouling hybrid composite, enriched with nanotubes loaded with different chemically active agents. The characterisation of the composites includes the examination of the physico-chemical properties, paying particular attention to their surface characteristics, in view of their use as antifouling paints.