Polymeric Coatings to Fight Biofouling

Abstract

Synonyms Antifouling coatings DefinitionBiofouling, the undesired accumulation of biomass on man-made surfaces, can be avoided by polymerbased surface coatings. BiofoulingBiofouling -the accumulation and growth of communities of organisms on natural or artificial surfaces in contact with aerial or saline environments -can have severe negative consequences in a multitude of fields including industrial processes (e.g., food processing, textile, pulp and paper manufacturing) and medicine (e.g., nosocomial infections) and on seawater-contacting equipment (e.g., pipelines, cooling and filtration systems, fishing nets, ship hulls, and bridge pillars). Biofilm Formation and Consequences of BiofoulingBiofouling is a complex process that, in most cases, can be described by a basic sequence of events. Firstly, the rapid adsorption of organic molecules (mainly proteins and polysaccharides) forms a conditioning film depending on the surface properties and the environmental conditions. This is quickly followed by the development of a microbial biofilm, which essentially involves (1) the attachment of bacteria cells (and diatoms), (2) the growth and multiplication of the attached cells, (3) the formation of mature colonies, and (4) cell detachment. In marine and freshwater environments, the microbial biofilms themselves influence the subsequent colonization with more complex organisms (e.g., algae spores and protozoa) by facilitating or inhibiting settlement. The final stage of fouling is characterized by the growth of macroalgae and the settlement and growth of larger marine invertebrates [1,2].Marine and freshwater biofouling is undesirable for many reasons. Microbial biofilms can cause local fluctuations in the concentration of various chemical species, such as oxygen and metal ions, thus accelerating the corrosion of the metal substrata. The metabolic process or products (e.g., sulfides) may also be corrosive to steel surfaces. Biofouling can increase the roughness on ship hulls, resulting in a greater hydrodynamic drag. The resulting increases in fuel consumption and maintenance costs (such as dry dock cleaning, paint removal, and repainting) cost the US Navy alone more than one billion dollars per annum. In addition to economic losses, a serious threat associated with marine biofouling is the global, distributive spread of invasive species that endanger local biodiversity [3,4].