• Korean Chemical Engineering Research
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• v.47 no.4
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• pp.476-480
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• 2009

A polymer composite electrolyte of a blend of poly(methyl methacrylate)(PMMA) and poly(ethylene oxide) (PEO) as a host polymer, the ethylene carbonate as a solvent, and $LiClO_4$ as a salt was studied. The crystallinity of the polymer electrolytes was evaluated using differential scanning calorimeter(DSC). The ionic conductivity of the polymer electrolytes was measured by frequency response analyzer(FRA) method. The effect of PEO/PMMA blend ratios on the ionic conduction in these electrolytes was investigated. The electrolyte films showed a phase separation due to immiscibility of the PMMA with the PEO. The PMMA-rich phase and the PEO-rich phase were produced during a film casting. The ionic conductivity of blend electrolyte was dependent on the content of PMMA and showed the highest value at 20 wt.%. However, when PMMA content exceeds 20 wt.%, the ionic conductivity was decreased due to the slow ionic transport through the PMMA-rich phase.

• Korean Journal of Materials Research
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• v.9 no.5
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• pp.446-451
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• 1999

Surface of Polymethylmethacrylate (PMMA) was modified by ion assisted reaction in which ion beam of Ar or$ O_2$is irradiated on polymer in reaction gas environment. Ion beam energy was changed from 600 to 1000eV, and ion doses were varied from $5\times10^{14} ions/cm^2 to 1\times10^{17} ions/cm^2$. Contact angle and surface energy of modified PMMA were measured by contact angle micrometer using distilled water and formamide. In the case of $Ar^+$ ion irradiation only, the contact angle reduced from $68^{\circ} to $35^{\circ}$ and the surface energy was changed from 46 dyne/cm to 60 dyne/cm. The contact angle significantly decreased to $14^{\circ}$and the surface energy increased to 72 dyne/cm when the surface of PMMA was modified by oxygen ion irradiation in oxygen gas environment. Improvement of wettability results from the formation of new hydrophilic group which is identified as C-O chain by XPS analysis. Recovery of wettability in dry air and maintenance of it in water condition were explained in view of the formation of hydrophilic group.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.4
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• pp.17-22
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• 2009

Two different organic-inorganic hybrid thin film transistors (OITFTs) with the structures of glass/ITO/ZnO/PMMA/Al (staggered structure) and glass/ITO/PMMA/ZnO/Al (inverted staggered structure), were fabricated and their electrical and structural properties were compared. The ZnO thin films used as active channel layers were deposited by the atomic layer deposition (ALD) method at a temperature of $100^{\circ}C$. To investigate the effect of the substrates on their properties, the ZnO films were deposited on bare glass, PMMA/glass and ITO/glass substrates and their crystal properties and surface morphologies were analyzed. The structural properties of the ZnO films varied with the substrate conditions. The ZnO film deposited on the ITO/glass substrate showed better crystallinity and morphologies, such as a higher preferred c-axis orientation, lower FWHM value and larger particle size compared with the one deposited on the PMMA/glass substrate. The field effect mobility ($\mu$), threshold voltage ($V_T$) and $I_{on/off}$ switching ratio for the OITFT with the staggered structure were about $0.61\;cm^2/V{\cdot}s$, 5.5 V and $10^2$, whereas those of the OITFT with the inverted staggered structure were found to be $0.31\;cm^2/V{\cdot}s$, 6.8 V and 10, respectively. The improved electrical properties for the staggered OITFTs may originate from the improved crystal properties and larger particle size of the ZnO active layer.

• Polymer(Korea)
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• v.37 no.5
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• pp.656-662
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• 2013

The flexible patterned cover film was made by a simple solution coating process using polymethyl methacrylate (PMMA) solution with glass beads. The effect of patterned cover film on the efficiency of solar cell has been investigated. It was found that the relative solar cell efficiency increased up to 3.4% with the incident light angle between $0-90^{\circ}$ by the sphere shape of glass bead coated on the film surface. This was understood that the loss of transmittance and scattering due to the light directional dependency on solar cell were minimized because the light entered glass beads normal to its surface regardless of incident light angle. The maximum relative solar cell efficiency was achieved when glass bead shape on the film is hemisphere and the relative efficiency increased with increasing the amount of glass bead on the film surface. However, too much glass beads on the film surface resulted in the lower relative solar cell efficiency due to the lowering of transmittance as well as the occurring of light interference.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.112-113
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• 2007

$SiO_2$ 절연 박막위에 희석된 PMMA 유기물을 처리하였다. 유기물 처리량에 따른 $SiO_2$ 박막의 $620{\sim}1100\;cm^{-1}$ 영역의 FTIR 스펙트라를 분석한 결과 0.3~0.7%로 PMMA 처리된 박막에서 친핵성 반응이 밀어나는 것을 확인하였으며, 친핵성 반응이 일어나는 박막들에서 누설전류가 적었으며, 절연특성이 우수한 것을 확인하였다.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2006.06a
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• pp.60-65
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• 2006

Previous studies demonstrated that laser ablation under transparent liquid can result in ablation enhacement and particle removal from the surface. In this work, the liquid-assisted excimer laser ablation process is examined fer polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), Si, and alumina with emphasis on ablation enhacement, surface topography, and debris formation. In the case of PET and PMMA, the effect of liquid is analyzed both fer thin water film and bulk water. As the ablation enhanement by liquid is already known for Si and alumina, the analysis focuses on surface topography and debris formation resulting from the liquid-assisted laser ablation process. The results show that application of liquid increases the ablation rate of PMMA while that of PET remains unchanged even in the liquid-assisted process. It is also revealed that the liquid can significantly improve the surface quality by reducing the debris deposition. However, the surface roughness is generally deteriorated in the liquid-assisted process. The surface toporaphy is found to be strongly dependent on the method of liquid application, i.e., thin film or bulk liquid.

• Proceedings of the KAIS Fall Conference
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• 2007.11a
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• pp.133-135
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• 2007

PMMA (polymethyl metha crylate) 유기막의 농도별 최적화를 위하여 1, 2, 4, 6, 8 wt.%의 PMMA 농도별로 Al/PMMA/ITO/Glass 구조의 MIM (metal- insulator-metal) 캐패시터 소자를 제작하였다. 유기 절연층의 형성은 ITO/Glass 기판 위에 PMMA를 용질로, Anisle을 용매로 사용하여 스핀코팅법으로 소자를 형성하였다. 제작된 소자에 대해 농도에 따른 전기적 특성을 조사한 결과 누설전류는 2wt.% 농도의 PMMA로 제작된 소자에서 0.3 pA로 가장 우수한 결과를 얻을 수 있었다. 또한 동일한 PMMA 농도로 제작된 캐패시터 소자의 정전용량은 1.2 nF으로 가장 좋은 결과를 얻을 수 있었으며, 계산된 값과 매우 유사한 값을 얻을 수 있었다.

• Applied Chemistry for Engineering
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• v.17 no.4
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• pp.397-402
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• 2006

We have investigated the effect of each ingredient in the light diffusing film (LDF) which was used as backlight unit (BLU) of TFT-LCD TV on physical, electrical, thermal and optical properties of LDF. In anti-blocking layer, the excellent anti-blocking ability was obtained when 0.5~1.5 wt% of acrylic bead was added, and good decay-time and water-stability were shown when 0.8 wt% of tertiary ammonium salt was added. Optimal results for adhesion strength, curing rates and flexibility on the surface of PET film have been obtained in the light diffusing layer by using acrylic polyol as a binder resin, and by addition of 30~35 wt% non-yellowing type HDI crosslinker. In addition, the highest normal luminance value was obtained by addition of 250 wt% poly-dispersive polystyrene ($20{\mu}m$ PS) and polymethylmethacrylate ($20{\mu}m$ PMMA) beads into the binder resin (100 wt%). The higher normal luminance could be got for PMMA beads than PS beads because of the transmittance difference.

• Journal of Adhesion and Interface
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• v.9 no.4
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• pp.30-33
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• 2008

Two polymeric interfaces with single component homo-polymers were prepared to control the orientation of block copolymer thin-film nanostructures. Poly(4-acetoxy styrene) (OH-PAS) and poly(4-methoxy styrene) (OH-PMS) which have the average chemical composition of polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) were precisely synthesized through nitroxide-mediated radical polymerization. After dehydration reactions between above polymers and SiOx layers of silicon wafers, the polymer-modified interface induced partial (30%) vertical orientation of PS-b-PMMA thin film in the case of OH-PMS and wholly parallel orientation in the case of OH-PAS. Chemical compositions of polymeric interface layers are regarded as the key parameter to control the orientation of nanostructures of block copolymer thin film.

• Journal of Adhesion and Interface
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• v.2 no.1
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• pp.18-22
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• 2001

Surface morphology of [poly(vinylidene fluoride)/poly(methyl methacrylate)] (PVDF/PMMA) was investigated on the basis of atomic force microscopy and differential scanning calorimeter measurements. The surface of (PMMA/PVDF) and (H14-PMMA/PVDF) blend films was fully composed with PVDF crystals. Although the difference of surface free energy between PMMA and PVDF is increased with increasing carboxyl group content in PMMA, however, in the case of (H24-PMMA/PVDF) blend film surface, the existence of aggregated H-PMMA was observed. It was found that the degree of surface enrichment of the blend is more affected by the magnitude of intermolecular interaction than the surface free energy difference, Besides, the introduction of carboxyl group for miscible (PVDF/PMMA) blend decreased the miscibility in the blend.