• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.2
• /
• pp.1216-1221
• /
• 2014

Poly(ethylene-co-isosorbide terephthalate) (PEIT) is interest in polymer which has isosorbide monomer that is renewable resources such as corn. However, there is important drawback which is low mechnical properties as increasing isosorbide contents. In this study, polycarbonate used to make up for drawback of mechanical properties of PEIT. In addition, PEIT used to improve the tensile elongation of polycarbonate because PEIT has good sheet proccessability. The effect of polycarbonate on morphology, thermal and mechanical properties were investigated using FE-SEM, DMA, TGA, UTM, and notched izod impact strength tester. As a result of this study, PEIT/PC blends were in compatible system and polycarbonate can act as an improvement of thermal stability and mechanical properties in the blends.

• Membrane Journal
• /
• v.25 no.6
• /
• pp.547-557
• /
• 2015

In this study, we synthesized polyimide with high carbon dioxide gas transport property using 2,2-bis(3,4-carboxylphenyl) hexafluoropropane, 2,3,5,6-tetramethyl-1,4-phenylenediamine and poly(ethylene glycol) bis(3-aminopropyl) terminated and then we calculated solubility parameter of synthesized polymer and non-solvent phase separation coefficient to determine proper solvent for preparation of asymmetric membrane, also we measured the viscosity of the polymer solution to check polymer contents in membrane solution and prepare asymmetric membrane with $LiNO_3$ additives. The morphology and gas separation property of membrane prepared by phase separation method was confirmed using Field Emission Scanning Electron Microsope and the single gas permeation measurement apparatus. We confirmed that the carbon dioxide permeance of the membrane increased and the selectivity showed little change with decreasing of the volatile solvent contents.

• Applied Chemistry
• /
• v.15 no.1
• /
• pp.17-20
• /
• 2011

A disposable light exposure detector kit has been developed by UV curing of a hydrogel material. The devised light exposure detector kit consisted of light sensitive structures, bottom plate, character sheet and sticky back plate. A light exposure detector kit has a serial light sensitive structures that contain various light sensitive dyes such as rhodamine and fluorescein. The light sensitive structure composed of UV curable hydrogel polymer material as a supporing material and photosensitive dye in a certain concentration. The fabrication procedure of the ligh exposure detector kit is very simple and fast due to UV curing procedure of a photopolymerizable hydrogel material such as poly(ethylene glycol) methyl ether acrylate (PEGMEA) and poly(ethylene glycol) diacrylate (PEGDA) with a photosensitive dye. By the proposed fabrication method, various size and shape of a light exposure detector kit could be fabricated using a flexible elastomer mold. Due to a fast and inexpensive fabrication method, the light exposure detector kit could be use a single use for various industrial applications. According to light irradation, the light sensitive structure on a light exposure detector kit could be lose its color by decomposition of a photosensitive dye chemical in the structure. Thus the amount of the exposed light on a substrate could easily be recognised by changing color or transparency of the structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.17-17
• /
• 2009

Single-walled carbon nanotubes (SWCNTs) have attracted much attention as promising materials for transparent conducting films (TCFs), thanks to their superior electrical conductivity, high mechanical strength, and complete flexibility. The CNT-based TCFs can be used in a variety of application fields as flexible, transparent electrodes, including touch panel screens, flexible electronics, transparent heaters, etc. First of all, this study investigated the effect of a variety of surfactants on the dispersion of SWCNTs in an aqueous solution. Following the optimization of the dispersion by surfactants, flexible TCFs were fabricated by spraying the CNT suspension onto poly(ethylene terephthalate) (PET) substrates. The sheet resistances of the TCFs having different surfactants were investigated with treatment in nitric acid ($HNO_3$) whose concentration and period of treatment time were varied. It seems that the $HNO_3$ removes the surfactants from and is simultaneously doped into the SWCNT network, reducing the contact resistance between CNTs. TCFs were characterized by UV-VIS spectroscopy, thermogravimetric analyzer (TGA), scanning electron microscopy (SEM), and four-point probe.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.254-254
• /
• 2009

Single-walled carbon nanotubes (SWCNTs) have attracted much attention as promising materials for transparent conducting films (TCFs), thanks to their superior electrical conductivity, high mechanical strength, and complete flexibility. The CNT-based TCFs can be used in a variety of application fields as flexible, transparent electrodes, including touch panel screens, flexible electronics, transparent heaters, etc. First of all, this study investigated the effect of a variety of surfactants on the dispersion of SWCNTs in an aqueous solution. Following the optimization of the dispersion by surfactants, flexible TCFs were fabricated by spraying the CNT suspension onto poly(ethylene terephthalate) (PET) substrates. The sheet resistances of the TCFs having different surfactants were investigated with treatment in nitric acid ($HNO_3$) whose concentration and period of treatment time were varied. It seems that the $HNO_3$ removes the surfactants from and is simultaneously doped into the SWCNT network, reducing the contact resistance between CNTs. TCFs were characterized by UV-VIS spectroscopy, thermogravimetric analyzer (TGA), scanning electron microscopy (SEM), and four-point probe.

• Proceedings of the KIEE Conference
• /
• 2007.11a
• /
• pp.98-99
• /
• 2007

This study has successfully demonstrated the direct fabrication of polymer resistors using ink-jet printing technology as an alternative patterning to traditional photolithography. The polymer resistors were fabricated just by two layer processes using a ink-jet printer (DMP-2800, Fujifilm Dimatix). First, resistive materials was patterned by a ink-jet printing with the desired width and length. Next, resistor fabrication was completed by printing metal contact pads on the both sides of the polymer resistor. We used poly (3,4-ethylene dioxythiophene) poly(styrenesulfonate)(PEDOT:PSS) for the resistor material and a nano-sized silver colloid for the metal contact pads. We characterized the electrical properties of PEDOT:PSS by measuring sheet resistance and specific resistance on a glass substrate. From analysis of the measured resistances, the electrical resistances of the polymer resistors linearly increased as a function of printed width and length of resistors. The accuracy of the fabricated polymer resistor showed about $0.6{\sim}2.5%$ error for the same dimensions.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.05a
• /
• pp.121.2-121.2
• /
• 2011

Aluminum-doped Zinc Oxide (AZO) is considered as an excellent candidate to replace Indium Tin Oxide (ITO), which is widely used as transparent conductive oxide (TCO) for electronic devices such as liquid crystal displays (LCDs), organic light emitting diodes (OLEDs) and organic solar cells (OSCs). In the present study, AZO thin film was applied to the transparent electrode of a channel-shaped flexible organic solar cell using a low-temperature selective-area atomic layer deposition (ALD) process. AZO thin films were deposited on Poly-Ethylene-Naphthalate (PEN) substrates with Di-Ethyl-Zinc (DEZ) and Tri-Methyl-Aluminum (TMA) as precursors and $H_2O$ as an oxidant for the atomic layer deposition at the deposition temperature of $130^{\circ}C$. The pulse time of TMA, DEZ and $H_2O$, and purge time were 0.1 second and 20 second, respectively. The electrical and optical properties of the AZO films were characterized as a function of film thickness. The 300 nm-thick AZO film grown on a PEN substrate exhibited sheet resistance of $87{\Omega}$/square and optical transmittance of 84.3% at a wavelength between 400 and 800 nm.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.28 no.1
• /
• pp.116-134
• /
• 2002

세리신은 누에고치의 고치실에서 추출되는 천연 단백질로서 많은 수산화기를 가지고 있어 뛰어난 보습성을 가진다. 이에 화장품에의 응용이 기대되나, 물에 잘 녹지 않는 특성을 가지고 있어서 화장품 원료로 사용하기에 어렵다는 단점이 있다. 본 연구에서는 친양쪽성 화합물인 poly(ethylene glycol)(PEG)을 세리신에 도입하여 수용성이며 자기조합형(self-assembled) 세리신-PEG 결합체를 합성하였다. 세리신내의 tyrosine 잔기의 방향 족 수산화기가 반응사이트임을 $^1$H-NMR 분석으로 알 수 있었으며, IR과 CD 측정으로 PEG 사슬의 도입으로 세리신의 구조가 불규칙한 coil구조에서 $\beta$-sheet구조로 구조적 변화가 일어남을 알 수 있었다. 또한 DSC 분석에서 세리신-PEG결합이후 각각의 녹는점이 떨어지는 것을 확인하여 상호 결정성에 영향을 주는 것을 확인하였다. 세리신-PEG 결합체는 자기조합하여 소수성 상호작용을 통해 200-400nm의 구형 나노입자를 이루며 투석방법을 통하여 얻을 수 있었다. 또한, 세리신-PEG 나노입자는 세리신자체보다 더 높은 보습력을 가지는 것을 확인하였다. 세리신-PEG 결합체의 cytotoxicity는 MTT assay에 의해 독성이 없음을 확인하였으며, 동물실험에 의한 독성도 전혀 나타내지 않음을 알 수있었다. 나노입자의 특성과 세리신의 보습성, 세리신-PEG의 친양쪽성 특성으로 세리신-PEG결합체 나노입자는 그 자체로도 원료로 사용 될 수 있을 뿐 아니라 생리 활성성분의 운반체로의 개발이 기대되어 진다.

• Polymer(Korea)
• /
• v.25 no.5
• /
• pp.657-664
• /
• 2001

In this study. the effects of ${\gamma}$-irradiation on the crosslinking of low density poly ethylene (LLDPE) and linear low density polyethylene (LLDPE) containing crosslinking agents were investigated to find the degree of crosslinking in the polymer. The LDPE and LLDPE specimens were prepared by blending crosslinking agents with each polymers, and by hot-press-molding into a sheet at 13$0^{\circ}C$. The ${\gamma}$-irradiation was conducted at 50 to 150 kGy in nitrogen. The crosslinking percentage in these specimens was measured in relation to the irradiation dose and the type of crosslinking agents. The mechanical properties, thermal properties and crystallinity of specimens were examined as a function of irradiation dose as well. It was found that the degree of crosslinking of the irradiated specimens was increased with increasing irradiation dose and by the addition of crosslinking agents. The mechanical properties and thermal properties of specimens were improved in proportion to an increase in the degree of crosslinking. The crystallinity of original resin was decreased with increasing crosslinking density.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.417-419
• /
• 2011

태양전지 모듈은 back sheet, 후면 충진재, 태양전지 cell, 전면 충진재, 전면 보호유리의 구성으로 되어 있다. back sheet는 유리 또는 금속을 사용하는데 사용 재료에 따라 각각 유리봉입방식, 슈퍼스트레이트방식으로 구분된다[1]. 태양전지를 보호하기 위한 충진재는 빛의 투과율 저하가 적은 PVB(Poly Vinyl Butylo)나 내습성이 뛰어난 EVA(Ethylene Vinyl Acetate) 등이 주로 이용된다. 유리봉입방식과 슈퍼스트레이트 방식의 공통점은 모듈 전면에 투과율과 내?충격 강도가 좋은 강화 유리를 사용하는 것이다. 하지만 현재 모듈의 전면 유리는 평탄한 표면 때문에 태양고도가 낮을 때 상대적으로 반사율이 높은 단점을 가지고 있다[2]. 이러한 문제점을 해결하기 위한 방안으로 표면 유리에 요철(anti-glare) 구조를 형성하면 평면 구조의 표면에서 반사되는 태양광이 일부 태양전지 내부로 재입사가 일어나게 되어 표면 반사율이 낮아지게 되고, 이로 인하여 태양전지의 효율이 증가하게 된다. 특히 이러한 효과는 태양고도가 낮아졌을 때 요철(anti-glare) 구조에 의한 반사율의 감소가 증가하기 때문에 평면 구조보다 요철(anti-glare) 구조의 태양전지 모듈 효율이 향상될 것이다. 본 논문에서는 요철(anti-glare) 구조를 만들기 위해서 유리와 평면 구조의 유리에서의 반사율과 투과율을 측정하여 비교 분석하였고, 특히 태양고도의 고도가 변할 때를 비교하기 위하여 반사율 및 투과율을 측정 할 때 입사광의 각도를 변화시켰다. 그리고 태양전지 cell 위에 요철(anti-glare) 구조의 유리와 평명 구조의 유리를 각각 위치시킨 후 태양전지 cell의 효율변화를 확인하였다. 이때 태양전지 cell의 표면은 이방성 식각 용액을 이용하여 역피라미드 구조의 텍스쳐링 태양전지 cell과 평면 구조의 태양전지 cell을 각각 사용하여 비교하였다.