• Journal of the Korean institute of surface engineering
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• v.56 no.4
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• pp.233-242
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• 2023

In recent years, energy-management studies in buildings have proven useful for energy savings. Typically, during heating and cooling, the energy from a given building is lost through its windows. Generally, to block the entry of ultraviolet (UV) and infrared (IR) rays, thin films of deposited metals or metal oxides are used, and the blocking of UV and IR rays by these thin films depends on the materials deposited on them. Therefore, by controlling the thicknesses and densities of the thin films, improving the transmittance of visible light and the blocking of heat rays such as UV and IR may be possible. Such improvements can be realized not only by changing the two-dimensional thin films but also by altering the zero-dimensional (0-D) nanostructures deposited on the films. In this study, 0-D nanoparticles were synthesized using a sol -gel procedure. The synthesized nanoparticles were deposited as deep coatings on polymer and glass substrates. Through spectral analysis in the UV-visible (vis) region, thin-film layers of deposited zinc oxide nanoparticles blocked >95 % of UV rays. For high transmittance in the visible-light region and low transmittance in the IR and UV regions, hybrid multiple layers of silica nanoparticles, zinc oxide particles, and fluorine-doped tin oxide nanoparticles were formed on glass and polymer substrates. Spectrophotometry in the UV-vis-near-IR regions revealed that the substrates prevented heat loss well. The glass and polymer substrates achieved transmittance values of 80 % in the visible-light region, 50 % to 60 % in the IR region, and 90 % in the UV region.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.404-405
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• 2018

• Textile Coloration and Finishing
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• v.18 no.5 s.90
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• pp.35-41
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• 2006

Upon $UV/O_3$ irradiation cellulose acetate (CA) films showed modified surface properties such as increased hydrophilicity and surface roughness as well as increased dyeability to cationic dyes. UV treatment induced photoscission of acetyl groups in the main chain of CA resulting in decreased degree of substitution from 2.2 to 1.3. The slight decreases in reflectance and transmittance were caused by remarkably increased nano-scale surface roughness of the CA surface as much as 20-fold, which can destructively interfere with visible lights of wavelength lower thu 500nm. Water contact angle decreased from $54^{\circ}\;to\;14^{\circ}$ with increasing UV energy. Surface energy also increased slightly. The surface energy change was attributed to significant contribution of polar component rather than nonpolar component indicating surface photooxidation of CA film. The increased dyeability to cationic dyes in terms of both K/S and %E may be due to photochemically introduced anionic and dipolar dyeing sites on the film surfaces.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.40-44
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• 2008

The interfacial adhesion energy between resist and a substrate is very important due to resist pull-off problems during separation of mold from a substrate in nanoimprint process. And effect of substrate surface roughness on interfacial adhesion energy is very important. In this paper, we have treated glass wafer surface using $CF_4$ gas for increase surface roughness and it has tested interfacial adhesion properties of UV resin/glass substrate interfaces by 4 point bending test. The interfacial adhesion energies by bare, 30, 60 and 90 sec surface treatments are 0.62, 1.4, 1.36 and 2 $J/m^2$, respectively. The test results showed quantitative comparisons of interfacial fracture energy (G) effect of glass wafer surface roughness.

• Textile Coloration and Finishing
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• v.20 no.6
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• pp.1-7
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• 2008

The effects of $TiO_2$ contents and UV irradiation treatment on the surface properties of PLA films embedded with $TiO_2$ nanoparticle were investigated. Whereas UV irradiation decreased reflectance of the treated PLA films proportionally with increasing UV energy, the reflectance of PLA/$TiO_2$ films increased with increasing UV energy. The UV irradiation treatment caused PLA/$TiO_2$ blend films more polar as indicated in the generation of new carbonyl group and decrease in zeta potentials, which was more pronounced with the introduction of $TiO_2$. Upon UV irradiation, $TiO_2$ particles appeared on the film surface as observed in SEM images. The PLA/$TiO_2$ blend films showed photocatalytic properties such as photobleaching of methylene blue, deodorization of ammonia and antimicrobial activity in comparison with pure PLA films.

• Elastomers and Composites
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• v.48 no.2
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• pp.167-171
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• 2013

Weatherability was examined according to aluminum particle size and its orientation used in PCM(Paint Coated Metal). Substrate delamination was checked by different UV transmission rate with QUV$^{(R)}$ (Q-LAB) equipment that can make accelerated UV irradiation. Film was prepared using three different types of conflake aluminum pastes under a PCM coating process and clearcoat was sprayed. UV transmission test results showed low transmission rate when EKART #790 having the smallest particle size and horizontal orientation was used. From the gloss retention results, gloss retention was highest in EKART #790 and followed by #770, #750.

• Current Photovoltaic Research
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• v.10 no.2
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• pp.49-55
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• 2022

With rapid growth in light-harvesting efficiency from 3.8 to 25.8%, organic-inorganic hybrid perovskite solar cells (PSCs) have attracted great attention as promising photovoltaic devices. However, despite of their outstanding performance, the commercialization of PSCs has been suffered from severe stability issues, especially for UV and humidity: (i) UV irradiation towards PSCs is able to lead UV-induced decomposition of perovskite films or catalytic reactions of charge-transporting layers, and (ii) exposure to surrounding humidity causes irreversible hydration of perovskite layers by the penetration of water molecules, resulting considerable decrease in their power-conversion efficiency (PCE). This review investigates current status of strategies to enhance UV and humidity stability of PSCs in terms of UV-management and moisture protection, respectively. Furthermore, the multifunctional approach to increase long-term stability as well as performance is discussed as advanced research directions for the commercialization of PSCs.

• Journal of the Korean Graphic Arts Communication Society
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• v.19 no.2
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• pp.68-78
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• 2001

UV-curable resin has the properties of quick-drying, thigh productivity at low temperature, energy savint, space saving, solventless, non-polluting and low-stinking, and thus, UV-curing system has been widely used in the fields of printing inks, adhesives, paints and coating agents. This study has been executed to micro-patterning used UV-curable resin, The micro-patterning properties of this photoresist were investigated under irradiation of UV light low pressure mercury lamp. When the exposed photoresist film was developed by pure water developer, the resolution of this photoresist was about 50$\mu\textrm{m}$.

• Elastomers and Composites
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• v.52 no.1
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• pp.22-26
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• 2017

The thermal conductivity and the adhesive properties were measured, after synthesis of thermal conductive composite which was obtained as a result of mixing alumina or graphite with acrylic adhesive synthesized by UV polymerization. The adhesive properties of the composite were evaluated measuring the peel strength at 180 degrees, the retention, and the initial tack;the thermal conductivity was estimated using laser flash analysis. As the filler contents increased, a decrease in peel strength and initial tack and an increase in retention and thermal conductivity were observed. When compared to alumina, the adhesion of graphite showed a dramatic decrease, whereas the thermal conductivity was further enhanced. It was found out that the small size of graphite increased the mechanical interlocking between the polymer and the filler, and it was easier for graphite to come into contact with other graphite in the matrix.

• Analytical Science and Technology
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• v.5 no.1
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• pp.135-142
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• 1992

Indium tin oxide(ITO) films coated on the window glass selectively transmit the solar energy and infrared. We call this system passive solar collectors. Selectively absorbing properties of sol gel dip coated ITO films were characterized by UV-VIS-NIR spectroscopy. The effects of heat treating temperature, time, atmosphere, substrate and barrier layers are concerned. Indium tin oxide films heat-treated at $500^{\circ}C$ in a reducing atmosphere show intrinsic properties. Efficiency of solar energy transmittance was enhanced by coating of $SiO_2-ZrO_2$ as an alkali ion barrier layer. Energy was saved by the double layers of $SiO_2-ZrO_2$ and ITO since solar energy is transmitted and heat generated inside(${\lambda}$ > 2700nm) is reflected.