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| 2. |
- Andersson Trojer, Markus, 1981, et al.
(författare)
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Imidazole and Triazole Coordination Chemistry for Antifouling Coatings
- 2013
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Ingår i: Journal of Chemistry. - : Hindawi Limited. - 2090-9063 .- 2090-9071. ; 2013
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Tidskriftsartikel (refereegranskat)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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| 3. |
- Andersson Trojer, Markus, 1981, et al.
(författare)
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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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Ingår i: Colloid and Interface Science Communications. - : Elsevier BV. - 2215-0382. ; 25, s. 36-40
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Andersson Trojer, Markus, et al.
(författare)
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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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Ingår i: Colloid and Polymer Science. - : Springer Science and Business Media LLC. - 0303-402X .- 1435-1536. ; 297:2, s. 307-313
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Tidskriftsartikel (refereegranskat)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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| 5. |
- Andersson Trojer, Markus, 1981, et al.
(författare)
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Use of microcapsules as controlled release devices for coatings
- 2015
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Ingår i: Advances in Colloid and Interface Science. - : Elsevier BV. - 0001-8686. ; 222, s. 18-43
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Arrhenius, Åsa, 1973, et al.
(författare)
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A novel bioassay for evaluating the efficacy of biocides to inhibit settling and early establishment of marine biofilms
- 2014
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Ingår i: Marine Pollution Bulletin. - : Elsevier BV. - 0025-326X. ; 87:1-2, s. 292-299
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a novel assay that allows a quick and robust assessment of the effects of biocides on the initial settling and establishment of marine photoautotrophic biofilms including the multitude of indigenous fouling organisms. Briefly, biofilms are established in the field, sampled, comminuted and re-settled on clean surfaces, after 72 h chlorophyll a is measured as an integrating endpoint to reflect both settling and growth. Eight antifoulants were used to evaluate the assay. Efficacy ranking, based on EC98 values from most to least efficacious compound is: copper pyrithione > TPBP > DCOIT > tolylfluanid > zinc pyrithione > medetomidine > copper (Cu2+), while ecotoxicological ranking (based on EC10 values) is irgarol, copper pyrithione > zinc pyrithione > TPBP > tolylfluanid > DCOIT > copper (Cu2+)>medetomidine. The algaecide irgarol did not cause full inhibition. Instead the inhibition leveled out at 95% effect at 30 nmol l−1, a concentration that was clearly lower than for any other of the tested biocides.
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| 7. |
- Arrhenius, Åsa, 1973, et al.
(författare)
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Combined effects of antifoulants – synergistic, additive or antagonistic effects?
- 2010
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Ingår i: the 15th International Congress on Marine Corrosion and Fouling, 25-29 July 2010, Newcastle.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Antifoulants are often used in combinations in paints. A survey of the scientific literatures shows that the effects of such antifoulant combinations are often predictable with a reasonable accuracy by the classical mixture toxicity concepts of Concentration Addition (CA) and Independent Action (IA). However, some studies also reported mixture effects that were substantially higher (synergistic) or lower (antagonistic) than predicted by either CA or IA. We therefore systematically explored the frequency and quantitative importance of such interactions within a group of 6 antifoulants using settling and growth of marine periphytic communities as the endpoint. All 15 possible 2-compound combinations that can be composed from the pool of six antifoulants were experimentally tested in three different ratios per mixture and their observed toxicity was compared to the predictions by CA and IA. The results show that the toxicities of the mixtures in most cases are at least roughly in agreement with the predictions, but that in several cases antagonistic effects occurred, which were related to the mixture-ratio and concentrations applied. No cases of synergism were observed for any of the investigated combinations. Implications for paint production as well as for the environment will be discussed. This study is part of the Marine Paint research programme funded by MISTRA, the Swedish Foundation for Strategic Environmental Research.
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| 8. |
- Arrhenius, Åsa, 1973, et al.
(författare)
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Effects of three antifouling agents on algal communities and algal reproduction: Mixture toxicity studies with TBT, Irgarol, and Sea-Nine
- 2006
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Ingår i: Archives of Environmental Contamination and Toxicology. - : Springer Science and Business Media LLC. - 0090-4341 .- 1432-0703. ; 50:3, s. 335-345
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Tidskriftsartikel (refereegranskat)abstract
- The toxicity of three antifoulants (Sea-Nine, Irgarol, and TBT) was determined individually and in mixtures in two tests with microalgae. Effects on periphyton community photosynthesis and reproduction of the unicellular green algae Scenedesmus vacuolatus were investigated. The tested antifoulants were highly toxic in both tests. Observed mixture toxicities were compared with predictions derived from two concepts: Independent Action (IA), assumed to be more relevant for the tested mixtures that were composed of dissimilarly acting substances, and Concentration Addition (CA), regarded as a reasonable worst-case approach in predictive mixture hazard assessment. Despite the corresponding mechanistic basis, IA failed to provide accurate predictions of the observed mixture toxicities. Results show the same pattern in both assays. Mixture effects at high concentrations were slightly overestimated and effects at low concentrations were slightly underestimated. Maximum observed deviations between observed and IA-predicted concentrations amount to a factor of 4. The suggested worst-case approach using CA was protective only in effect regions above 20%. Nevertheless, the application of any concept that accounts for possible mixture effects is more realistic than the present chemical-by-chemical assessment
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| 10. |
- Arrhenius, Åsa, 1973, et al.
(författare)
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Marine Paint Optimisation: settling assays with marine periphyton communities and sea lettuce (Ulva lactuca)
- 2008
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Ingår i: The 14th International Congress on Marine Corrosion and Fouling, July 27-31, 2008, Kobe, Japan.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the Marine Paint Optimisation project the major groups of fouling organisms will be studied. From each group of organisms one model organism was selected and used in settling assays to assess the efficacy of a number of individual antifoulants. A tentative list of existing and promising compounds include medetomidine, tolylfluanide, copper pyrithione, Sea-Nine, Irgarol, copper, Borocide, and Econea. Based on the produced data we will predict the joint effects of almost all possible combinations in terms of efficacy. The optimisation will be based both on high efficacy and low environmental risk. We will present and summarise the results from two settling assays with marine biofilms (microfouling) and the zoospores of the macroalga sea lettuce (Ulva lactuca). The microfoulers are important parts of the fouling community with a high number of different species and individuals which form the basis for all subsequent settlers. In this periphyton assay a multispecies microbial biofilm established in the field on Plexi glas (PMMA) are used to prepare an inoculum using a scrape, shake and sieve technique. Using this approach we include a large set of the potential species in the microbial fouling community. Ulva lactuca belongs to the most common family of fouling macroalgae. Thalli of Ulva lactuca were sampled in the field in September 2007, cultivated in the laboratory until further testing of the zoospores. Both assays are semistatic and run over three days and include both settling and growth. Efficacy data for a number of antifouling agents will be presented. This study is part of the Marine Paint research programme funded by MISTRA.
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