• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.484.1-484.1
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• 2014

Bulk hetero junction (BHJ) polymer solar cells (PSCs) are one of the most promising fields as alternative energy source. Especially, the development of new p-type conjugated polymer is one of the main issues to get core technology. In this study, a series of varied ratio of 3,6-carbazole in poly[9-(heptadecan-9-yl)-9H-carbazole-2,7-diyl-alt-(5,6-bis-(octyloxy)-4,7-di(thiophen-2-yl)benzo-[1,2,5]-thia-diazole)-5,5-diyl] were designed and synthesized. These polymers have good solubility and film formability than PCDTBT which is well known promising material. Investigation of the photovoltaic properties of these new polymers indicated that polymer with 2% of 3,6-carbazole provided higher PCE (3.8% to 4.9%) with enhanced JSC, FF, VOC. We found origin of this improvement using several methods, one of which is reduced bimolecular recombination in polymer.

• Rapid Communication in Photoscience
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• 제4권1호
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• pp.16-18
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• 2015

Luminescence properties of anthracene chromophores were investigated. Anthracene chromophores were incorporated in cyclosiloxane-based hybrid polymers through one-pot hydrosilylation reaction. Using four-armed cyclosiloxanes, divinylterminated siloxane monomers, and 9-vinylanthracenes, anthracene-labeled hybrid polymers were prepared. Free-standing hybrid polymer films were prepared successfully by doctor-blade method and thermal treatment. The polymer films exhibit strong blue fluorescence from anthracene and its fluorescence lifetime was not influenced by the temperature, indicating that the movement of anthracene chromophores was restrained in cyclosiloxane-based hybrid polymer films.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 가을 학술발표회 논문집
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• pp.169-170
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• 2003

There was little development in transparent conductive polymer films and their limited studies have been mainly focused on polymer films coated by water-soluble PEDOT doped with the polymeric counteranion poly(4-styrenesulfonate) (PEDOT-PSS)[1-3]. However PEDOT-PSS as coating material has some difficulties because of high viscosity and low solubility in organic solvent except for in water. In this study, in order to extend practical applications of PEDOT and to prepare conductive PC films, we tried to prepare PEDOT-coated PC films and investigated their conductivity and thermal stability. (omitted)

• Fibers and Polymers
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• 제3권3호
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• pp.103-108
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• 2002

The viscosity effect of matrix polymer on melt exfoliation behavior of an organoclay in poly($\varepsilon$-caprolactone) (PCL) was investigated. The viscosity of matrix polymer was controlled by changing the molecular weight of poly($\varepsilon$-eaprolactone), the processing temperature, and the rotor speed of a mini-molder. Applied shear stress facilitates the diffusion of polymer chains into the gallery of silicate layers by breaking silicate agglomerates down into smaller primary particles. When the viscosity of PCL is lower, silicate agglomerates are not perfectly broken into smaller primary particles. At higher viscosity, all of silicate agglomerates are broken down into primary particles, and finally into smaller nano-scale building blocks. It was also found that the degree of exfoliation of silicate layers is dependent upon not only the viscosity of matrix but thermodynamic variables.

• Bulletin of the Korean Chemical Society
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• 제23권4호
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• pp.571-574
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• 2002

The photorefractive polymeric composite with good performance was prepared. The carbazole-substituted polysiloxane sensitized by 2,4,7-trinitro-9-fluorenone was used as a photoconducting medium and 1-[4-(2-nitrovinyl)phenyl]piperidine was added as an optically nonlinear chromophore. The photorefractive property of polymer was determined by diffraction efficiency using a 100 ㎛-thick film. The maximum diffraction efficiency ( ηmax) of 71% was obtained at the electric field of 70 V/ ㎛. The potential of the current polymer material as a holographic recording medium was evaluated by the demonstration of holographic recording and subsequent reading of optical image.

• Journal of Welding and Joining
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• 제31권4호
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• pp.23-27
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• 2013

Laser heat source was used for automotive interior and exterior parts to reduce weights. Typically, 900's nm wavelength of laser has been widely used for polymer joining, however, the transmittance of the laser beam thorough clear polymers such as PMMA or PC has been an issue to overcome. To solve this issue, 1,940nm laser was applied on the clear polymer for the better absorption and 900nm laser beam was used for main laser for the joining. Conventional Gaussian or Elliptical heat source approximation has limitation in polymer which had deeper skin depth where major laser beam absorbs. To accurately simulate the physical laser beam absorption and joining optical properties were experimentally measured for the computer FEM simulation. The simulation results showed close correlation between theoretical and experimental results. The developed laser process is expected to increase productivity and gap closing which can cause failure of joining in laser material processing.

• 멤브레인
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• 제14권1호
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• pp.53-56
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• 2004

Direct Methanol Fuel Cell (DMFC) is considered as a candidate technology for applications in stationary, transportation as well as electronic power generation purposes. To develop a high performance direct methanol fuel cell(DMFC), a competent electrolyte membrane is needed. The electrolyte membrane should be durable and methanol crossover must be low. One of the approaches to increase the stability of generally used polymer electrolyte membranes such as Nafion against swelling or thermal degradation is to bond it with an inorganic material physically or chemically. In Noritake Company, we have developed a novel method of reinforcing the polymer electrolyte matrix with inorganic fibers. Methanol crossover values measured were significantly lower than the original polymer electrolyte membranes. These fiber reinforced electrolyte membranes (FREM) were used for DMFC study and stable power output values as high 160 mW/$\textrm{cm}^2$ were measured. The details of the characteristics of the membranes as well as I-V data of fuel cell stacks are detailed in the paper.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1227-1228
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• 2006

The electrochemical properties of novel metal powders were investigated for the electrode materias of polymer electrolyte memebrane electrolysis. Two types of Pt black and $IrO_2$ powder electrodes were hot-pressed on the polymer electrolyte membrane to form membrane electrode assembly. The galvanodynamic polarization methode was used to characterize the electrochemical properties of both electrodes. From the experimental results, we concluded that the $IrO_2$ powder electrode exhibits better electrochemical performance than Pt black as cathode material for the electrolysis.

• 한국세라믹학회지
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• 제51권2호
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• pp.127-131
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• 2014

Precipitated calcium carbonate(PCC) inorganic fillers for plastic offera higher replacement ratio with improved mechanical properties than any other inorganic fillers. Due to its secure economic feasibility, its fields of application areexpanding. For optimized PCC grain size and polymer replacement ratio, it is good to maintain at least $0.035{\mu}m$ grains and keep double the grain size of distance between particles, depending on the molecular weight and volume replacement rate of the polymer. PCC has unique characteristics, ie, with smaller grain size, dispersibility decreases, and if grain size is not homogenous, polymer cracking occurs. The maximum replacement ratio of PCC is approximately 30%, but in the range of 10 - 15% it produces the highest mechanical strength. When mixed with a biodegradable plastic like starch, it also improves initial environmental degradability.

• 반도체디스플레이기술학회지
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• 제12권2호
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• pp.93-98
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• 2013

Nanoimprint lithography (NIL) is a next generation technology for fabrication of micrometer and nanometer scale patterns. There have been considerable attentions on NIL due to its potential abilities that enable cost-effective and high-throughput nanofabrication to the display device and semiconductor industry. To successfully imprint a nanosized pattern with the thermal NIL, the process conditions such as temperature and pressure should be appropriately selected. This starts with a clear understanding of polymer material behavior during the thermal NIL process. In this paper, a filling process of the polymer resist into nanometer scale cavities during the thermal NIL at the temperature range, where the polymer resist shows the viscoelastic behaviors with consideration of stress relaxation effect of the polymer. In the simulation, the filling process and the residual layer formation are numerically investigated. And the effects of pressure and temperature on NIL process, specially the residual layer formation are discussed.