Designer coatings fail to stop ocean fouling in real-world tests
Scientists tested four advanced polymer coatings designed to repel marine organisms—bacteria, algae, and barnacles—that cost shipping and offshore industries billions yearly. While the coatings showed promise in lab tests, they lost effectiveness within weeks in actual ocean conditions, suggesting the industry needs fundamentally different approaches to solve the biofouling problem.
Originaltitel: Charged hydrophilic polymer brushes and their relevance for understanding marine biofouling
<p>The resistance of charged polymers to biofouling was investigated by subjecting cationic (PDMAEMA), anionic (PSPMA), neutral (PHEMA-<em>co</em>-PEG<sub>10</sub>MA), and zwitterionic (PSBMA) brushes to assays testing protein adsorption; attachment of the marine bacterium <em>Cobetia marina</em>; settlement and adhesion strength of zoospores of the green alga <em>Ulva linza</em>; settlement of barnacle (<em>Balanus amphitrite</em> and <em>B. improvisus</em>) cypris larvae; and field immersion tests. Several results go beyond the expected dependence on direct electrostatic attraction; PSPMA showed good resistance towards attachment of <em>C. marina</em>, low settlement and adhesion of <em>U. linza</em> zoospores, and significantly lower biofouling than on PHEMA-<em>co</em>-PEG<sub>10</sub>MA or PSBMA after a field test for one week. PDMAEMA showed potential as a contact-active anti-algal coating due to its capacity to damage attached spores. However, after field testing for eight weeks, there were no significant differences in biofouling coverage among the surfaces. While charged polymers are unsuitable as antifouling coatings in the natural environment, they provide valuable insights into fouling processes, and are relevant for studies due to charging of nominally neutral surfaces.</p>