Biofouling - the colonisation of submerged surfaces by aquatic organisms - is a major problem for all marine industries. Fouling on surfaces results in corrosion, a decrease in hydrodynamic efficiency, transport of introduced pests, and many other problems worldwide. The major focus of fouling and antifouling technologies has been in the marine shipping industry, where fouling is estimated to cost the industry >$5 billion per year. Fouling is also a major problem for the aquaculture industry. Currently, the major strategy for combating fouling is via the use of heavy - metal based (copper, tin), toxic, antifouling paints.

 

Motivated by environmental and industry concerns over the use of copper based antifouling paints, researchers at the CMB developed coatings which release either commercial compounds or natural seaweed derived metabolites, to be used on salmon cages; and coatings based on physical mechanisms, to be used in shellfish aquaculture, all with demonstrated efficacy under commercial conditions. Some of these aquaculture coatings developed in collaboration with the CRC for Aquaculture and CSIRO were  successfully licensed to Wattyl and marketed as PearlSafe or Netsafe.

 

Currently, the CMB is developing novel approaches to antifouling coatings. The approach is based on three general kinds of technologies:

 

1. Living paints

2. Enzyme-based coatings

3. 'non-stick', low surface energy coatings

 

The living paints technology represents a revolutionary way of approaching the problem of marine antifouling. Traditionally, harmful toxins such as tin, copper and or zinc have been used to poison the organisms that attempt to settle on surfaces in the marine environment. However, this metal approach unintentionally poisons other species and is not completely effective since some target organisms are

naturally resistant to them. One way nature prevents such fouling (shown on conspicuously clean surfaces in the marine environment) is the use of bacteria that release natural chemicals to deter marine species from settling. One such species of bacteria is Pseudoalteromonas tunicata which releases no less than 5 separate antifouling chemicals.

Knowledge of polymer substrates to provide a ‘polymer home’ for such bacteria where they are free to grow and thrive, has resulted in significantly reduced fouling on a surface for 7 weeks in Sydney Harbour. This is the first scientific approach demonstrated in the field environment. The enzyme-based coatings involves producing catalytic effects off the surface of typical household coatings utilising added enzymatic mixtures. Applications such as self-cleaning coatings have been the driver of this technology. Coatings that contain additives to transport enzymes to the surface and make them available for substrate interaction have been optimised. Methods of fluoroescently monitoring enzyme concentrations within the coating depth have also been implemented in this study. Pilot scale production of these coatings is now the main focus of this study program.

 

The 'non-stick', low surface energy coatings, inhibit fouling through physical means, either via low surface energies or microtopographies.

For any queries on this project please contact Dr. Lachlan Yee