| 1. |
- Andersson Trojer, Markus, 1981, et al.
(author)
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Imidazole and Triazole Coordination Chemistry for Antifouling Coatings
- 2013
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In: Journal of Chemistry. - : Hindawi Limited. - 2090-9063 .- 2090-9071. ; 2013
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Journal article (peer-reviewed)abstract
- Fouling of marine organisms on the hulls of ships is a severe problem for the shipping industry. Many antifouling agents are based on five-membered nitrogen heterocyclic compounds, in particular imidazoles and triazoles. Moreover, imidazole and triazoles are strong ligands for Cu2+ and Cu+, which are both potent antifouling agents. In this review, we summarize a decade of work within our groups concerning imidazole and triazole coordination chemistry for antifouling applications with a particular focus on the very potent antifouling agent medetomidine. The entry starts by providing a detailed theoretical description of the azole-metal coordination chemistry. Some attention will be given to ways to functionalize polymers with azole ligands. Then, the effect of metal coordination in azole-containing polymers with respect to material properties will be discussed. Our work concerning the controlled release of antifouling agents, in particular medetomidine, using azole coordination chemistry will be reviewed. Finally, an outlook will be given describing the potential for tailoring the azole ligand chemistry in polymers with respect to Cu2+ adsorption and Cu2+ Cu+ reduction for antifouling coatings without added biocides.
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| 2. |
- Andersson Trojer, Markus, 1981, et al.
(author)
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Polymer Core-Polymer Shell Particle Formation Enabled by Ultralow Interfacial Tension Via Internal Phase Separation: Morphology Prediction Using the Van Oss Formalism
- 2018
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In: Colloid and Interface Science Communications. - : Elsevier BV. - 2215-0382. ; 25, s. 36-40
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Journal article (peer-reviewed)abstract
- The internal phase separation technique is a versatile method for liquid core-polymer shell formation, yet limited to very hydrophobic core materials and actives. The use of polymeric cores instead circumvents this restriction due to the absent mixing entropy for binary polymer mixtures which allows the polymeric core (and the active) to approach the polarity of the shell. Polystyrene core-shell and janus particles were formulated using polymethylmethacrylate, poly(lactic acid), poly(lactic acid-co-glycolic acid), poly(epsilon-caprolactone) or cellulose triacetate as shell-forming polymers. The morphology and the partitioning was experimentally determined by selectively staining the core and the shell with beta-carotene and methylene blue respectively. In addition, the van Oss formalism was introduced to theoretically predict the thermodynamic equilibrium morphology. As elucidated using the theoretical predictions as well as experimental optical tensiometry, it was found that the driving force for core-shell morphology is, in contrast to liquid core-polymer shell particles, a low core-shell interfacial tension.
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| 3. |
- Andersson Trojer, Markus, et al.
(author)
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Use of anchoring amphiphilic diblock copolymers for encapsulation of hydrophilic actives in polymeric microcapsules : methodology and encapsulation efficiency
- 2019
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In: Colloid and Polymer Science. - : Springer Science and Business Media LLC. - 0303-402X .- 1435-1536. ; 297:2, s. 307-313
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Journal article (peer-reviewed)abstract
- Aqueous core-shell particles based on polystyrene, poly(methyl methacrylate) or polycaprolactone have been formulated using a facile double emulsion-based solvent evaporation method. The size distribution is narrow, and the morphology control is remarkable given the simple characteristics of the encapsulation method. The inner droplets are stabilized by oil-soluble poly(ethylene oxide)-based block copolymers which are anchored in the polymeric shell by using hydrophobic blocks of the same type as that of the shell-forming polymer. This facilitates the efficient encapsulation of dyes and hydrophilic biocides. [Figure not available: see fulltext.].
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| 4. |
- Andersson Trojer, Markus, 1981, et al.
(author)
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Use of microcapsules as controlled release devices for coatings
- 2015
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In: Advances in Colloid and Interface Science. - : Elsevier BV. - 0001-8686. ; 222, s. 18-43
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Journal article (peer-reviewed)abstract
- Biofouling of surfaces is a considerable problem in many industrial sectors and for the public community in general. The problem is usually approached by the use of functional coatings and most of such antifouling coatings rely on the effect of biocides. However, a substantial drawback is the poor control over the release of the biocide as well as its degradation in the paint. Encapsulation of the biocides in microcapsules is a promising approach that may overcome some of the problems associated with the more traditional ways of incorporating the antifouling agent into the formulation. In this review, we summarize more than a decade of microcapsule research from our lab as well as from other groups working on this topic. Focus will be on two coacervation-based encapsulation techniques; the internal phase separation method and the double emulsion method, which together enable the encapsulation of a broad spectrum of biocides with different physicochemical properties. The release of the biocide from core-shell particles and from encapsulated biocides in coatings is treated in detail. The release behaviour is interpreted in terms of the physicochemical properties of the core-shell particle and the coating matrix. In addition, special attention is given to the experimental release methodology and the implementation of proper diffusion models to describe the release. At the end of the review examples of antifouling properties of some coatings against common biofoulers are presented.
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| 5. |
- Blanck, Hans, 1950, et al.
(author)
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A retrospective analysis of contamination and periphyton PICT patterns for the antifoulant irgarol 1051, around a small marina on the Swedish west coast
- 2009
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In: Marine Pollution Bulletin. - : Elsevier BV. - 0025-326X .- 1879-3363. ; 58, s. 230-237
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Journal article (peer-reviewed)abstract
- Irgarol is a triazine photosystem II (PSII) inhibitor that has been used in Sweden as an antifouling ingredient since the 1990s. Early microcosm studies indicated that periphyton was sensitive to irgarol at concentrations regularly found in harbours and marinas. However, field studies of irgarol effects on the Swedish west coast in 1994, using the pollution-induced community tolerance (PICT) approach, failed to detect any effects of the toxicant in the field. A PICT study involves sampling of replicate communities in a gradient of contamination, and a comparison of their community tolerance levels, with an increase being an indication that sensitive species have been eliminated and replaced by more tolerant ones. Typically, short-term assays are used to quantify the community tolerance levels. Later PICT studies in the same area over a 10 year period demonstrate that irgarol tolerance levels have increased, although the contamination pattern has been stable. Our results support the hypothesis that that the PICT potential was low initially, due to a small differential sensitivity between the community members, and that a persistent selection pressure was required to favour and enrich irgarol-tolerant species or genotypes. © 2008 Elsevier Ltd. All rights reserved.
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| 6. |
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| 7. |
- Blanck, Hans, 1950, et al.
(author)
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New strategy for design of optimised combinations of antifoulants: mixture efficacy predictions, risk weighting and microcapsule technology
- 2008
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In: 14th International Congress on Marine Corrosion and Fouling, July 2008, Kobe Japan.
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Conference paper (peer-reviewed)abstract
- Organisms differ in their sensitivity to toxicants, and each biocide will have its own efficacy profile. Whenever an antifoulant is used to affect organisms beyond its high-efficacy profile, an excess of biocides will be emitted to the environment. We propose an unprejudiced and rational design of efficacy-optimised combinations with minimum environmental risk. To control release of several antifoulants independently we use microcapsules bound to a polymer coating. The approach is based on three initial steps: Mixture toxicity concepts are used to predict efficacy of >100 000 combinations of 2-8 antifoulants. Predictions are based on full concentration-efficacy relationships with regard to prevention of settling of fouling model organisms (e.g. periphyton, sea lettuce, barnacles, sea squirt, blue mussel). Based on the predictions we will identify a set of > 100 000 combinations that are efficacious to all model organisms, and define their mixture concentrations and mixture ratios. Risk ratios (e.g. PEC/ PNEC) for the individual antifoulants are then used as weighing factors to rank the combinations according to their estimated relative risk to the environment. This results in a set of promising antifoulant combinations defined by their constituents, mixture ratios and total concentrations in water. The release rate from each of the individual mixture components will be regulated by microcapsule numbers, chemical and physical properties, to deliver the expected combination at the surface of the ship hull. The flexibility of the paint formulation ・with one antifoulant only in each capsule ・suggests that the coating can easily be reformulated to adjust to more demanding conditions. This study is a part of the Marine Paint Research Programme funded by MISTRA, the Foundation for Strategic Environmental Research, Sweden.
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| 8. |
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| 9. |
- Dahlbäck, Björn, et al.
(author)
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The Challenge to Find New Sustainable Antifouling Approaches for Shipping
- 2010
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In: Coastal Marine Science. - 1349-3000. ; 34:1, s. 212-215
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Journal article (other academic/artistic)abstract
- Fouling of ships and its counter measure – antifouling – is receiving justified attention as a serious marine environmental problem. If the ship is fouled its fuel consumption will increase radically. If a ship is fouled its emissions to air will increase, its manoeuvrability will be affected and it will contribute to the spreading of aliens. The present antifouling strategies seem to be non-sustainable, either environmentally or technically/commercially. The large amounts of biocides used in antifouling paints constitute a marine pollution problem. Research for more sustainable solutions, biocidal as well as non-biocidal, is ongoing. Optimisation of new antifoulant combinations combined with microcapsule technology will offer the possibility to decrease the exposure of the marine environment to antifouling biocides.
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| 10. |
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