optimization of Antifouling coatings incorporating butenolide a potent Antifouling Agent via field and laboratory tests

Rosin-based Antifouling paint with the incorporation of butenolide, a promising antifoulant, possesses the potential to deter the settlement of marine organisms on submerged surfaces. With the purpose to extend the Antifouling duration, this research investigated the respective contribution of paint ingredients, including butenolide concentrations (5%, 10% and 15%), pigment choices (TiO2, Fe2O3, Cu2O and ZnO) and binder compositions (acrylic copolymer to rosin at 1: 2.5, 1.5: 2 and 2.5: 1), to the field Antifouling performance of butenolide. A raft trial was carried out at Yung Shue 0, Hong Kong after the application of Antifouling paints on PVC panels. Biofouling dynamics on panel surfaces, such as coverage percentage and biomass accumulation, were monitored until submersion for 6 months to allow for the assessment of Antifouling efficiency. Field results showed that butenolide incorporation generally inhibited the settlement of fouling species on the coated panels as demonstrated by the decreased surface coverage and biomass weight. Coatings with 1: 2.5 paints containing 10% butenolide exhibited the best Antifouling performance with only 34% of the surface covered by fouling organisms, which mainly consisted of algae and slime. The smallest biomass increase of the fouling community was also observed for 1: 2.5 coatings. An increased proportion of rosin in binder compositions yielded better Antifouling performance following the order of 1: 2.5 > 1.5: 2 > 2.5: 1. Laboratory experiments were also conducted to examine the behavior of paint coatings in stirring artificial seawater. Butenolide addition decreased the film hardness and inhibited water uptake, but resulted in weight loss of paint coatings. Along with the gradual release of butenolide, the hardness of paint films increased gradually. Overall, a service life of 6 months, while eliminating the use of heavy metals, highlights the effectiveness of butenolide-incorporated paint formulation, especially 1: 2.5 paint, as an environmentally benign and fouling-resistant candidate for future Antifouling application.

linking genomic responses of gonads with reproductive impairment in marine medaka oryzias melastigma exposed chronically to the chemopreventive and Antifouling Agent 3 3 diindolylmethane dim

3,3′-Diindolylmethane (DIM) has been promoted as an effective chemopreventive and Antifouling additive. However, the concurrent risks or side effects of DIM are not fully understood, especially on tissues responsive to estrogen. Therefore, this study employed marine medaka (Oryzias melastigma) as a test model to evaluate relative safety and explore mechanisms of toxic action of DIM on development and function of gonad after chronic (28days) aqueous exposure to relatively low doses (0μg/L or 8.5μg/L). Integration of comprehensive toxicogenomic analysis at the transcriptome and proteome levels with apical endpoints, such as production of eggs and swimming performance of larvae, elucidated the molecular linkage in gonad from bottom up along the reproductive adverse outcome pathway. A series of sequential changes at the transcript and protein levels were linked to lesser fecundity and viability of larvae exposed to DIM. Anomalous production of vitellogenin (VTG) and eggshell proteins in testis confirmed the estrogenic potency of DIM. In the ovary, although storage of VTG was greater, lesser expressions of cathepsin enzymes blocked cleavage and incorporation of VTG into oocytes as yolk, which acted together with lower eggshell proteins to inhibit maturation of primary oocyte and thus contributed to impairment of fecundity. Overall, this study demonstrated that exposure to DIM impaired reproductive fitness. Diverse molecular initiating changes in gonads were linked to apical endpoints that could be used in assessment of risks posed by DIM on gametogenesis. In combination with chemical stability and potent endocrine disruption, the results of this study can inform decisions about the use of DIM either as chemopreventive or Antifouling Agent.

degradation kinetics of a potent Antifouling Agent butenolide under various environmental conditions

Abstract Here, we investigated the degradation kinetics of butenolide, a promising Antifouling compound, under various environmental conditions. The active ingredient of the commercial antifoulant SeaNine 211, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), was used as positive control. The results showed that the degradation rate increased with increasing temperature. Half-lives of butenolide at 4 °C, 25 °C and 40 °C were >64 d, 30.5 d and 3.9 d, respectively. Similar half-lives were recorded for DCOIT: >64 d at 4 °C, 27.9 d at 25 °C and 4.5 d at 40 °C. Exposure to sunlight accelerated the degradation of both butenolide and DCOIT. The photolysis half-lives of butenolide and DCOIT were 5.7 d and 6.8 d, respectively, compared with 9.7 d and 14.4 d for the dark control. Biodegradation led to the fastest rate of butenolide removal from natural seawater, with a half-life of 0.5 d, while no obvious degradation was observed for DCOIT after incubation for 4 d. The biodegradative ability of natural seawater for butenolide was attributed mainly to marine bacteria. During the degradation of butenolide and DCOIT, a gradual decrease in Antifouling activity was observed, as indicated by the increased settlement percentage of cypris larvae from barnacle Balanus amphitrite . Besides, increased cell growth of marine diatom Skeletonema costatum demonstrated that the toxicity of seawater decreased gradually without generation of more toxic by-products. Overall, rapid degradation of butenolide in natural seawater supported its claim as a promising candidate for commercial Antifouling industry.

Imidazole and Triazole Coordination Chemistry for Antifouling Coatings

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.

Antifouling Agent Release from Marine Coatings – Ion Pair Formation/Dissolution for Controlled Release

In marine coatings, the ability to sustain constant release of Antifouling Agents (AFA(s)) over a long period of time has become increasingly important. One efficient approach to prevent that diffusion depletes the paint film’s Antifouling activity is to adsorb the AFA strongly to a specie with low translational mobility, such as a high molecular weight polymer. Therefore, the AFA, Medetomidine, was adsorbed onto a sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SDPS) generating a Medetomidine-SDPS ion pair in an organic solvent. The interaction was investigated by 1 H NMR in butanol (BuOH-d 10 ) and on solid surfaces by the quartz crystal microbalance with dissipation monitoring technique (QCM-D) in two different solvents, seawater and o-xylene. From the NMR studies in butanol (BuOH-d 10 ), a strong interaction between Medetomidine and SDPS was observed. From the QCM-D measurements, differences in affinity between Medetomidine and the SDPS was observed when changing from seawater to o-xylene. In seawater, the interaction was weak and displayed a large degree of reversibility compared to in o-xylene, where the interaction was strong and almost irreversible. Different swelling behaviour was also observed at the solid surfaces depending on the solvent used with o-xylene exhibiting the largest swelling of the polymer layer. © 2006 Elsevier B.V. All rights reserved.

Antifouling Agent release from marine coatings ion pair formation dissolution for controlled release

In marine coatings, the ability to sustain constant release of Antifouling Agents (AFA(s)) over a long period of time has become increasingly important. One efficient approach to prevent that diffusion depletes the paint film’s Antifouling activity is to adsorb the AFA strongly to a specie with low translational mobility, such as a high molecular weight polymer. Therefore, the AFA, Medetomidine, was adsorbed onto a sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SDPS) generating a Medetomidine-SDPS ion pair in an organic solvent. The interaction was investigated by 1 H NMR in butanol (BuOH-d 10 ) and on solid surfaces by the quartz crystal microbalance with dissipation monitoring technique (QCM-D) in two different solvents, seawater and o-xylene. From the NMR studies in butanol (BuOH-d 10 ), a strong interaction between Medetomidine and SDPS was observed. From the QCM-D measurements, differences in affinity between Medetomidine and the SDPS was observed when changing from seawater to o-xylene. In seawater, the interaction was weak and displayed a large degree of reversibility compared to in o-xylene, where the interaction was strong and almost irreversible. Different swelling behaviour was also observed at the solid surfaces depending on the solvent used with o-xylene exhibiting the largest swelling of the polymer layer. © 2006 Elsevier B.V. All rights reserved.

altered expression level of escherichia coli proteins in response to treatment with the Antifouling Agent zosteric acid sodium salt

Summary

Zosteric acid sodium salt is a powerful Antifouling Agent. However, the mode of its Antifouling action has not yet been fully elucidated. Whole cell proteome of Escherichia coli was analysed to study the different protein patterns expressed by the surface-exposed planktonic cells without and with sublethal concentrations of the zosteric acid sodium salt. Proteomic analysis revealed that at least 27 proteins showed a significant (19 upregulated and 8 downregulated, P < 0.001) altered expression level in response to the antifoulant. The proteomic signatures of zosteric acid sodium salt-treated cells are characterized by stress-associated (e.g. AhpC, OsmC, SodB, GroES, IscU, DnaK), motility-related (FliC), quorum-sensing-associated (LuxS) and metabolism/biosynthesis-related (e.g. PptA, AroA, FabD, FabB, GapA) proteins. Consistent with the overexpression of LuxS enzyme, the Antifouling Agent increased autoinducer-2 (AI-2) concentration by twofold. Moreover, treated cells experienced a statistically significant but modest increase of reactive oxygen species (+ 23%), tryptophanase (1.2-fold) and indole (1.2-fold) synthesis. Overall, our data suggest that zosteric acid sodium salt acts as environmental cue leading to global stress on E. coli cells, which favours the expression of various protective proteins, the AI-2 production and the synthesis of flagella, to escape from adverse conditions.

Altered expression level of Escherichia coli proteins in response to treatment with the Antifouling Agent zosteric acid sodium salt

Summary

Zosteric acid sodium salt is a powerful Antifouling Agent. However, the mode of its Antifouling action has not yet been fully elucidated. Whole cell proteome of Escherichia coli was analysed to study the different protein patterns expressed by the surface-exposed planktonic cells without and with sublethal concentrations of the zosteric acid sodium salt. Proteomic analysis revealed that at least 27 proteins showed a significant (19 upregulated and 8 downregulated, P