• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.754-761
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• 2017

UV-curable hydrophilic coating solutions were prepared by mixing colloidal silica dispersed in alcohol with an acrylic monomer, pentaerythritol triacrylate (PETA). Hydrophilic coating films were also prepared by spin coating the hydrophilic coating solutions on PC substrates and UV curing for 10 minutes subsequently. The effect of the amount of colloidal silica in the coating solutions, which was varied from 10 g to 50 g, was investigated on the hydrophilic properties of UV-cured coating films. The results showed that the amount of colloidal silica had a great influence on the hydrophilic properties of UV-cured coating films and the coating film prepared with 30 g of colloidal silica showed a lowest contact angle of $37^{\circ}$ and an excellent pencil hardness of H.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.6
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• pp.725-732
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• 1999

It is usual to use hydrophilic-coated aluminum foil for evaporator fin of air-conditioners to reduce air flow resistance caused by the water droplets condensed on the fin surface. The major effect of a hydrophilic coating is to reduce the contact angle of the condensate and prevent bridging of the condensate between the adjacent fins. The performance of hydrophilic coating generally tends to be degraded as it is used since the coating material is washed down by the condensate. In the present work, several types of hydrophilic coatings were evaluated in terms of durability of hydrophilicity, corrosion resistance and heat resistance. Results showed that an improved hydrophilic coating of resin type presented superb qualify in terms of durability and corrosion resistance while having almost the same level of qualify in heat resistance compared with the others.

• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.830-836
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• 2017

Hydrophilic coating solutions were prepared by reacting a silane coupling agent, GPTMS (3-glycidoxypropyl trimethoxysilane) with colloidal silica. Hydrophilic coating films were also obtained by depositing the hydrophilic coating solutions on polycarbonate substrates by spin-coating and subsequently by thermal curing at $120^{\circ}C$. During this process, the effect of average particle sizes of colloidal silica was studied on the properties of coating films. As a result, coating film, prepared from colloidal silica with average particle size of 25 nm, showed a low contact angle of $20^{\circ}$ and a good pencil hardness of H. On the other hand, coating films, prepared from colloidal silica with average particle sizes of 15 nm and 45 nm, exhibited high contact angles of $27^{\circ}$ and $36^{\circ}$ and pencil hardness of H and B, respectively.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.247-252
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• 2017

Hydrophilic coating solutions were prepared by reacting a silane coupling agent, aminosilane with colloidal silica (15~20 nm in diameter). Hydrophilic coating films were also obtained by depositing the hydrophilic coating solutions on polycarbonate substrates by dip-coating and subsequently by thermal curing at $120^{\circ}C$. During this process, the effect of types of aminosilane was studied on the properties of coating films. As a result, coating films, prepared with 3-aminopropyltriethoxysilane (APTES) as aminosilane, showed contact angles of $25{\sim}44^{\circ}$ and a poor pencil hardness of B. On the other hand, coating films, prepared with 3-aminopropyltrimethoxysilane (APTMS) as aminosilane, exhibited contact angles of $26{\sim}37^{\circ}$ and a good pencil hardness of 2H.

• Korean Membrane Journal
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• v.7 no.1
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• pp.19-27
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• 2005

PP hollow fiber membrane was hydrophilized by EVOH dip coating followed by low temperature plasma treatment and UV irradiation. EVOH coating attained high water flux without any prewetting but its stability did not guaranteed at high water permeation rate. At high water permeation rate, water flux declined gradually due to swelling and delamination of the EVOH coating layer causing pore blocking effect. However, plasma treatment reduces the swelling, which suppress delamination of the EVOH coating layer from PP support result in relieving the flux decline. Also, UV irradiation helped the crosslinking of the EVOH coating layer to enhance the performance at low water permeation rate. FT-IR and ESCA analyses reveal that EVOH dip coating performed homogeneously through not only membrane surface but also matrix. Thermogram of EVOH film modified plasma treatment and W irradiation show that crosslinking density of EVOH layer increased. Chemical modification by plasma treatment and UV irradiation stabilized the hydrophilic coating layer to increase the critical flux of the submerged membrane.

• KIEAE Journal
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• v.11 no.6
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• pp.133-138
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• 2011

This paper presents energy self-sufficiency simulated in municipal wastewater treatment plants (WWTPs) by adopting solar energy production systems that were simulated by varying azimuth and super-hydrophilic coating on the surface of photovoltaic (PV). Relative to the national average energy consumption in WWTPs, the employment of 100 kW PV system was simulated to achieve 2.75% of energy self-sufficiency. The simulated results suggested that the installation of PVs toward South or Southwest would produce the highest energy self-sufficiency in WWTPs. When super-hydrophilic coating was employed in the conventional PV, 5% of additional solar energy production was achievable as compared to uncoated conventional PV. When 100 kW of PV system was installed in a future test-bed site, Kihyeung Respia WWTP located in Yongin, South Korea, the energy self-sufficiency by solar power was simulated to be 1.77%. The simulated solar power production by azimuth and super-hydrophilic coating will be useful reference for practitioners in designing the solar PV systems in the WWTPs.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.163-170
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• 2016

In order to improve the hydrophilic property of polymer films, coating solutions which showed a good hydrophilic property, were prepared by the sol-gel method. The coating solutions were prepared by adding different types of silane coupling agents (aminosilane, epoxysilane and acrylsilane) to a colloidal silica (15 nm diameter). The solutions prepared by adding aminosilane resulted in gels which could not be used as coating solutions. On the other hand, the coating solutions prepared by the addition of epoxysilane showed contact angles of $10{\sim}15^{\circ}$ and good hydrophilic property at R=0.10~0.15 (R=silane coupling agent/colloidal silica weight ratio). In addition, the coating solutions prepared by the addition of acrylsilane at R=0.03~0.07, exhibited contact angles of $5{\sim}10^{\circ}$, which means better hydrophilic property than aminosilane or epoxysilane.

• Journal of the Korean Applied Science and Technology
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• v.33 no.3
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• pp.483-491
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• 2016

Even though the antifogging property of nanosilica coated glass surface is highly increased due to the hydrophilic hydroxyl groups on nanosilica surface, the durability of this property on outdoor glass was diminished rapidly after rain washing. In addition the topology of nanosilica coated glass surface plays very important roles to control an light transmittance or antireflection property. To improve these coating durability and characteristics a hydrophilic nanosilica coating on glass was prepared by coating with 1.5 wt% of nanosilica (Ludox) suspension in the presence of hydrolyzed tetraethylorthosilicate (TEOS). The optimum hydrolysis condition of TEOS in acidic or basic aqueous solution was also examined by contact angle measurement. The final transparent hydrophilic coating layer coated with nanosilica-TEOS in acidic condition (pH=4) showed much improved durability of hydrophilic surface as well as higher visible light transmittance than original uncoated glass by 2 % point.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.318-318
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• 2006

4-Vinylbenzyl maltohexaoside peracetate, 1, was copolymerized with divinylbenzene using the initiator for nitroxide-mediated living radical polymerization, 2, to afford the polystyrene microgel with acetyl maltohexaose, 3. The deacetylation of 3 was achieved by treatment with sodium methoxide in dry 1,4-dioxane to produce the polystyrene microgel with maltohexaose, 4. A good coating property of the polystyrene microgel was combined with an excellent hydrophilic property derived from maltohexaose. In addition, 4 showed the ability to solubilize fullerene in aqueous solution. Therefore, 4 has a potential application as a special coating using functional but incompatible compounds such as fullerene on the surface of various hydrophilic materials.

• Journal of the Korea Safety Management & Science
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• v.1 no.1
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• pp.259-272
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• 1999

In order to enhance the selectivity, productivity and yield of methyl fructoside, which was synthesized by enzymatic glycosylation of sucrose and methanol solution, controlling of surface property of solid support using different immobilization procedures optimized microenvironment of immobilized invertase. Silanization and polyethylene imine coating methods were adopted to give a hydrophobic and hydrophilic environment of immobilized invertase. As a result, polyethyleneimine coating method gave higher loading of enzyme, effective activity, and relative activity than silanization method, because it brought on increasing the functional density of amino group and enhancing the conservation of activity by regulating of hydrophilicity. And then, hydrophilic environment was possible to restraint the assessing of methyl fructoside molecule, which was more hydrophobic than sucrose, fructose, and glucose molecule in the reaction mixture, into .the active site of immobilizedinvertase. Consequently, hydrophilic microenvironment of immobilized invertase by polyethyleneimine coating obtained higher yield and productivity with increasing conversion than silanized and native invertase. Thus, this procedure optimized the microenvironment of immobilized invertase suitable for the enzymatic synthesis of methyl fructoside.