Archive: Trends in antifouling research and development
The actual requirement for the performance of antifouling systems is multifold: Prevention of micro- and macrofouling, reduction of friction to reduce emissions, composed of biodegradable compounds, active irrespective of operational profile and degree of activity, and applicable in dockyard conditions. It is obviously a challenge hard to meet.
Nevertheless, conferences and research projects are dealing to meet all these goals at once and screening presentations on international meeting show a wide range of foci on fundamental aspects of biofilm formation, adhesion, settlement cues and interactions in the fouling community (www.conferencealerts.com/show-event?id=125818). To give an impression of research trends in Europe selective projects, funding and awards are recorded.
In the EU project SEAFRONT fouling control coatings shall be developed within the four-year timeframe which will not leach chemical or other harmful substances that are non-biodegradable in the marine environment. In addition, the coatings will reduce the hydrodynamic resistance of ships and boats, decreasing fuel consumption and thus substantially reducing CO2 emissions. Finally, the new coatings will lead to considerable savings in operational costs by improving the efficiency of tidal power installations and reducing the frequency of maintenance and cleaning in off-shore infrastructure and aquaculture applications. The Dutch Polymer Institute is the project coordinator and International Paint Ltd., will bring any new coatings based on technology developed within the project to the market. In addition to the development of environmentally friendly coatings, SEAFRONT aims to significantly enhance the fundamental understanding of fouling organisms and the mechanisms of settlement and adhesion (www.polymers.nl).
Fostering research to develop sustainable antifoulants, the UK Technology Strategy Board awarded £500,000 ($837,400 USD) to a consortium of businesses and universities. The group secured the award from the UK's Technology Strategy Board to co-fund a two-year project to develop s ustainable, high-performance, marine coatings. AkzoNobel will oversee the project, which partners the company's International Paint business with the University of Liverpool, Revolymer plc and Newcastle University (www.innovateuk.org).
Some months ago AkzoNobel has developed a carbon credits scheme based on the performance of its Intersleek marine coating. The scheme benefits participants by allowing them to turn fuel savings that come from using the coating into carbon credits. Vessel operating data collected by AkzoNobel forms the basis for an award of carbon credits, which is handled by a separate company. The credits can then be traded or sold. These savings would go some way to make Intersleek, which is two to three times more expensive than other products in the sector, competitive. The carbon credits are managed by the Gold Standard Foundation, which was set up by WWF (www.international-marine.com/carboncredits).
The goal of the EU funded LEAF project is to reduce the use of biocide in antifouling coatings, reduce to zero the release of this substance in the surrounding water, and extend the service life of antifouling coatings. The approach is not based on the exposure and release of biocide into the water. Instead it is based on the direct contact between biocide residing inside a coating and fouling organisms such as the barnacles. The technical challenge of the project is to find the optimal combination of biocide/coating matrix in order to completely eliminate the release of biocides. The biocide used was Ivermectin, a Macro-cyclic Lactone (ML) of microbial origin, which was present in the paint in trace amounts (0,1% w/v). The leaching rate of ML from the paint formulation was absent, or below 1 ng/cm/day. The aim of the project is to make further optimization of the formulation in terms of selection of alternative binder system to completely eliminate release (even if already practically zero) and select optimum co-biocide package or alternative solutions to reach a more holistic antifouling spectra, being effective on algae and slime forming biofilms. The ultimate goal is to make a metal-free, emission free, marine anti-fouling coating with a service life of at least 10 years (www.leaf-antifouling.eu).
ADAM4EVE - Adaptive and smart materials and structures for more efficient vessels is an EU-project that focuses on the development and assessment of applications of adaptive and smart materials and structures in the shipbuilding industry. Materials and structures are called adaptive if they can change certain properties in a predictable manner due to the forces acting on them (passive) or by means of built in actuators (active). Those materials and structures are referred to as smart if they provide best performance when operation circumstances change. The goal is to develop adaptable ship hull structures for optimized hydrodynamic properties depending on varying cruise speed, smart underwater coatings with antifouling properties in harbor and low resistance during voyage and adaptive materials for noise and vibration damping of ship engines to avoid induction of vibrations into the ship hull and adaptive outfitting materials that improve ships‟ serviceability and safety www.adam4eve.eu
Along with an actual trend to incorporate biocides into non-stick coatings like silicones or rubber, non-biocidal modifications to enhance the performance are possible.
One trend to improve the performance of silicone-based non-stick coatings with respect to slime prevention PPG Industries has launched a 100% silicone-binder system that uses surface regeneration technology to maintain a slime-resistant substrate.PPG says "This results in an increased silicone density at the surface to such a degree that slime organisms do not it as a surface substrate and have no chance to settle on it," Water acts as a catalyst to reduce the coating's surface energy "back to its original state and thus restart its beneficial surface configuration properties," according to PPG (www.sigmacoatings.com).
Carnival Foundation is providing a $2.5-million gift over five years to support The Nature Conservancy’s efforts in protecting the marine environment.
The development of novel, durable, low-surface energy coatings with antifouling (ice, insects, biofouling etc.) and low friction properties is believed to be a promising direction for research with benefit to the transportation, construction and power generation sectors. Conventional coatings and surface treatments have not been successful in this area because of a lack of long-term durability and limited repellency of environmental fouling agents.
New nanostructured coatings, which can be deposited from the liquid state, shall offer a potential solution that can be easily industrially adopted. However, there is a lack of standardization regarding their characterization and performance evaluation. The strategy selected by TWI and Brunel University to link the properties and structure of high-performance coatings from the nano to macro scale is described and is illustrated by the presentation of some provisional results. Functionalized nanostructured silica species have been used to reinforce an acrylate matrix leading to retention of the hydrophobicity even after aggressive abrasive wear (Wojdyla et al. 2014).
Wojdyla, A. M., G. G. Durand, A. Taylor & I. W. Boyd (2014): Advanced low‐energy durable coatings. International Journal of Energy Research 39(2), 165-171.