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- Yandi, Wetra, et al.
(författare)
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Antialgal activity of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes against the marine alga Ulva
- 2017
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Ingår i: Biofouling (Print). - : TAYLOR & FRANCIS LTD. - 0892-7014 .- 1029-2454. ; 33:2, s. 169-183
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Tidskriftsartikel (refereegranskat)abstract
- Marine biofouling has detrimental effects on the environment and economy, and current antifouling coatings research is aimed at environmentally benign, non-toxic materials. The possibility of using contact-active coatings is explored, by considering the antialgal activity of cationic poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes. The antialgal activity was investigated via zoospore settlement and sporeling growth assays of the marine algae Ulva linza and U. lactuca. The assay results for PDMAEMA brushes were compared to those for anionic and neutral surfaces. It was found that only PDMAEMA could disrupt zoospores that come into contact with it, and that it also inhibits the subsequent growth of normally settled spores. Based on the spore membrane properties, and characterization of the PDMAEMA brushes over a wide pH range, it is hypothesized that the algicidal mechanisms are similar to the bactericidal mechanisms of cationic polymers, and that further development could lead to successful contact-active antialgal coatings.
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| 2. |
- Yandi, Wetra, et al.
(författare)
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Charged hydrophilic polymer brushes and their relevance for understanding marine biofouling
- 2016
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Ingår i: Biofouling (Print). - : Taylor & Francis. - 0892-7014 .- 1029-2454. ; 32:6, s. 609-625
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Tidskriftsartikel (refereegranskat)abstract
- The resistance of charged polymers to biofouling was investigated by subjecting cationic (PDMAEMA), anionic (PSPMA), neutral (PHEMA-co-PEG10MA), and zwitterionic (PSBMA) brushes to assays testing protein adsorption; attachment of the marine bacterium Cobetia marina; settlement and adhesion strength of zoospores of the green alga Ulva linza; settlement of barnacle (Balanus amphitrite and B. improvisus) cypris larvae; and field immersion tests. Several results go beyond the expected dependence on direct electrostatic attraction; PSPMA showed good resistance towards attachment of C. marina, low settlement and adhesion of U. linza zoospores, and significantly lower biofouling than on PHEMA-co-PEG10MA 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.
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| 3. |
- Yandi, Wetra, et al.
(författare)
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Hydration and Chain Entanglement Determines the Optimum Thickness of Poly(HEMA-co-PEG(10)MA) Brushes for Effective Resistance to Settlement and Adhesion of Marine Fouling Organisms
- 2014
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society. - 1944-8244 .- 1944-8252. ; 6:14, s. 11448-11458
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Tidskriftsartikel (refereegranskat)abstract
- Understanding how surface physicochemical properties influence the settlement and adhesion of marine fouling organisms is important for the development of effective and environmentally benign marine antifouling coatings. We demonstrate that the thickness of random poly(HEMA-co-PEG(10)DMA) copolymer brushes affect antifouling behavior. Films of thicknesses ranging from 50 to 1000 angstrom were prepared via surface-initiated atom-transfer radical polymerization and characterized using infrared spectroscopy, ellipsometry, atomic force microscopy and contact angle measurements. The fouling resistance of these films was investigated by protein adsorption, attachment of the marine bacterium Cobetia marina, settlement and strength of attachment tests of zoospores of the marine alga Ulva linza and static immersion field tests. These assays show that the polymer film thickness influenced the antifouling performance, in that there is an optimum thickness range, 200-400 angstrom (dry thickness), where fouling of all types, as well as algal spore adhesion, was lower. Field test results also showed lower fouling within the same thickness range after 2 weeks of immersion. Studies by quartz crystal microbalance with dissipation and underwater captive bubble contact angle measurements show a strong correlation between lower fouling and higher hydration, viscosity and surface energy of the poly(HEMA-co-PEG(10)MA) brushes at thicknesses around 200-400 angstrom. We hypothesize that the reduced antifouling performance is caused by a lower hydration capacity of the polymer for thinner films, and that entanglement and crowding in the film reduces the conformational freedom, hydration capacity and fouling resistance for thicker films.
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