• Clean Technology
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• v.23 no.2
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• pp.148-157
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• 2017

To prepare UV-curable polyurethane-acrylate oligomer, NCO-terminated urethane prepolymers with trimethylolpropane, [TMP; 0 (0), 0.1 (0.021) and 0.2 (0.043) mole (mole fraction)] as crosslinkable tri-functional chain extender were end-capped with pentaerythritol triacrylate [PETA; 2.0 (0.400), 1.7 (0.354) and 1.4 (0.304) mole (mole fraction)] with one hydroxyl group/three vinyl functionalities. The stable as-formulated UV-curable polyurethane-acrylates [stable mixtures of PETA-capped oligomer/reactive acrylic monomer diluents without/with heptadecafluorodecyl methacrylate (PFA; 0, 6 and 9 wt%)] were formed up to 0.2 (0.043) mole (mole fraction) of TMP content in the prepolymer, while homogeneous-mixing failed at 0.3 (0.068) mole (mole fraction), in which the crosslink density in NCO-terminated urethane prepolymer was too high to enable the formation of stable mixture. This study examined the effect of TMP/PETA molar ratio and heptadecafluorodecyl methacrylate (PFA) content (wt%) on the properties of UV-cured polyurethane-acrylates as marine antifouling coating materials. The properties of UV-cured polyurethane-acrylate were found to be significantly dependent on the crosslinkable TMP/PETA ratio and PFA content. With the increasing of the TMP and PFA contents, the contact angles increased, and consequently the surface tension decreased. The adhesion of algae/barnacles to PFA contained film samples were found to be sufficiently weak to allow their easy removal. These results suggest that the UV-cured samples containing PFA have strong potential as coating materials for antifouling applications.

• Textile Coloration and Finishing
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• v.30 no.1
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• pp.9-19
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• 2018

To prepare bio-inspired antifouling coating materials having similar structure with lotus, self-crosslinkable waterborne polyurethanes emulsions containing paraffin wax (CWPU/P0, 0.25, 0.5, 1.0, 1.5, 2.0, the number indicated the wt% of wax) were prepared by an emulsifier-free/solvent free prepolymer mixing process. The as-polymerized CWPU/P emulsions containing 0 - 1.00wt% of paraffin wax were found to be stable after 4 months, however, CWPU/P emulsions containing 1.50 and 2.00wt% of paraffin wax were unstable within 1 month storage. Considering the stability of emulsions, the optimum paraffin wax content was found to be about 1wt% to obtain stable antifouling coating emulsion material. The surface topology of CWPU/P film samples was characterized by atomic force microscopy (AFM). This study examined the effect of paraffin wax content on the surface roughness, water contact angle/surface energy, water swelling, light transmittance and tensile properties of CWPU/P film samples.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.3
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• pp.137-142
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• 2021

In this study, the development of the room temperature curable silica-based coating compositions for anticorrosive and antifouling performance in marine environments was carried out. The marine (plant) structures with many exposed parts are operated in harsh marine environments such as strong ultraviolet rays, extreme temperature differences and salt water corrosion. Organic paints that are easily degraded under these environments and easily eroded by physical stimuli such as waves can not play a role properly. Dense ceramic coatings on marine structures provide careful protections even in saltwater environments due to their high hardness and rust resistance. Therefore, in the case of ceramic coatings, their use and application range in marine structures can be greatly improved due to their functional advantages. In the present study, silica-based coating compositions based on colloidal silica with silane coupling agents, curing salts, and ceramic fillers were developed, and their applications as protective coatings for corrosion protection and fouling prevention in seawater were also studied.

• Korean Journal of Environmental Biology
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• v.17 no.3
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• pp.315-319
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• 1999

Spore attachment of Ulva fasciata on agar and agaroses coating films showed various surfaces properties according to concentrations of agar or agaroses or via methanol. The highest number of spore attachment occurred in Sigma agarose coating film. Spore attachment on Bacto agar and other agaroses coating films showed the 12 ∼ 36 times less than Sigma agarose coated film. Comparison of spore attachment on 2.5% and 5％ Seakem agarose and Bacto agar coating films differed in two concentrations while coating of 2.5% and 5％ with NuSieve and Sigma agaroses did not differed. Spore attachment of coating made of 5％ and 5% via 4% MeOH with Bacto agar and Nusieve agarose only differed. Overall, these results indicated agar and agarose coating films differed in spore attachment. Results of this work will be useful baseline for bioassay of antifouling activity of fouling organisms.

• Corrosion Science and Technology
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• v.4 no.4
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• pp.155-163
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• 2005

Heavy duty coating are required to have minimum durable period of 15 years under average usage environment because these paints are coated with purpose of anti-corrosion, antifouling, plastering etc. Onto steel structures constructed upon land and sea and other ferrous structures of electric power generation plants, electricity transmission towers, large structures of various plants, etc. Therefore we tried to estimate heavy duty coating longevity through reliability evaluation method and used combined cyclic anti-conrrosion test method composed of drying, moisturizing and salt spray as for accelerated life test to estimate longevity. Accelerated life test hours to heavy duty coating of first grade (with longevity not less than 15 years) specification may be obtained from troubleless test hours $t_n=\frac{B_p}{n^{1/\beta}}\left[\frac{1n(1-CL)}{1n(1-p)} \right]^{1/\beta}=19.671$ (yr) where shape parameter $\beta=1.1$, confidence level CL=80 %, warranty life $B_{10}=15$ yr and sampling size n=10 (2 sets). Because acceleration factor {AF} found by accelerated test is 41.7, accelerated life test hours required may be represented about 4,132 hr so that if this amount of hours is converted to number of cycles(6 hr/cycle) of complex cycle corrosion resistance test then the amount is tantamount about 690 cycles. That means if there does not occur trouble failure (with defect factor sum not more than 20) during when there is performed 690 cycles of combined cyclic anti-corrosion test to heavy duty coating specimen then it signifies that there can be warranted longevity $B_{10}$ of 15 yr under condition of confidence level CL=80 %.

• Tribology and Lubricants
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• v.29 no.5
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• pp.304-309
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• 2013

Shark skin has functionalities such as self-cleaning and antifouling; it also exhibits excellent drag reduction owing to a hierarchical structure of microgrooves and nanometer-long chain mucus drag reduction interfaces around the shark body. In this study, the wettability of a shark skin surface and its replicas are evaluated. First, a shark skin template is taken from a real shark. Then, shark skin replicas are produced directly from a shark skin template, using a micromolding technique. The quantitative replication precision of the shark skin replicas is evaluated by comparing the geometry of the shark skin template to the replica using 2D surface profiles. Contact angles at the solid-air-water interfaces are evaluated for the shark skin template and its replicas under two conditions: with and without hydrophobic coating. The results show that the microriblets on shark skin improve the hydrophobic feature and play a critical role in self-cleaning.

• Journal of Environmental Health Sciences
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• v.29 no.3
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• pp.1-8
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• 2003

The development of environmentally nontoxic or non-polluting antifouling additives that can be formulated in practical coating requires assay involving target organisms. Described here are the simple laboratory assays that have been developed using the barnacle, Balanus amphitrite, a common fouling organism found throughout temperate and tropical seas. One of the assays depends on synchronous year-round mass culture, the procedure for which is described, of nauplii larvae and cyprids larvae. The laboratory assays provided quantitative estimates of toxicity and settlement inhibition of the test compounds. Laurinterol (1), isolaurinterol (2), alpysinal (3), and aplysin (4) have been isolated from the Korean red alga Laurencia okamurae. Their structures were identified by spectral data in comparison with the literature data. Compounds 1-4 inhibited larval settlement of the barnacle B. amphitrite with EC$_{50}$ values of 0.18- 36 $\mu\textrm{g}$/ml. Com-pounds 2-4 showed larval toxicity against nauplii of the barnacle B. amphitrite with 5-10 $\mu\textrm{g}$/ml, while laurinterol (1) exhibited no toxicity at even 100 $\mu\textrm{g}$/ml. Therefore, laurinterol was expected as a promising natural antifoulant.t.

• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.176-179
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• 2008

• KSBB Journal
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• v.23 no.3
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• pp.226-230
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• 2008

In this study we have studied adhesive properties of various microorganisms onto surfaces of phosphorylcholine-based copolymer for the application of optical biosensors. Three microorganisms, E.coli JM109, B.cereus 318, P.pastoris X-33 were cultivated in confocal cultivation dishes with glass surface, respectively. The glass surface was coated with copolymer containing 0% 5% and 10% MPC (2-methacryloxyethyl phosphorylcholine). After cultivation, culture medium was discarded and adhered microorganisms were dyed by gram staining method. Adhered microorganisms were analyzed using an optical microscope and scanning electronic microscope (SEM). A great number of microorganisms, $2-3{\times}10^3/mm^2$ were adhered on the surfaces of glass and copolymer membrane without MPC. But the antifouling effects of copolymer containing 5% and 10% phosphorylcholine were large, that microorganisms of less than $50-100/mm^2$ were attached on the copolymer membranes. Thus, the copolymer containing phosphorylcholine is very useful as an antifouling coating material for optical biosensor.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.2
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• pp.120-129
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• 2023

Marine structures are subject to damage not only from sea salt but also from the adhesion of marine microorganisms and suspended particles, which cause additional damages. In order to prevent this, periodic coating is employed in the case of vessels to maintain the necessary performance. However, it is true that periodic coating is difficult for concrete or steel support structures, and there is a risk of marine environmental pollution. In this study, authors developed an anti-fouling coating agent using eco-friendly materials that possess hydrophilic cellulose nanofibers and AKD(alkyl ketene dimer). To achieve a homogeneous mixture, the content of cellulose nanofibers was fixed at 1 %, and AKD, distilled water, and waste glass were mixed using a digital mixer and homogenizer. The contact angle of the prepared coated surface was observed to be over 130°, indicating sufficient performance even in a water droplet flow test with a 15° slope, suggesting self-cleaning capability. Furthermore, through the analysis of viscosity characteristics at different temperatures, it was confirmed that the application is feasible at room temperature. Microstructure analysis also verified that the coating agent is uniformly applied to the concrete surface.