• 대한화장품학회지
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• 제25권4호
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• pp.123-131
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• 1999

Liquid crystal known as a rheological barrier to coalescence of oil droplets, increases emulsion stability, water-holding capacity and promotes active material penetration to skin. Some investigation for its rheological characteristics have been reported but its relations to consumer perception have been rarely published. In this study, oil/water emulsion and oil/liquid crystal/water systems were manufactured using the same composition or Behenyltrimethylammonium chloride/Cetostearyl alcohol/Lanolin oil. and rheological properties or each system were investigated with Cone and Plate rheometer. The formation of liquid crystalline phase was observed with polarized microscope and Differential Scanning Calorimeter. Continuous shear experiment, creep, yield and water holding capacity were measured for oil/water and oil/liquid crystal/water systems. The results were compared with sensory evaluations. Oil/liquid crystal/water system showed higher,viscosity at the same shear rate. higher viscoelasticity and higher yield stress than oil/water system. These properties were expected to show good spreadability and excellent richness without waxiness in hair can: products of creme type. This expectation was consistent with the results of sensory experiments. Water-holding capacity was evaluated by measuring residual water of specimens at specific temperature and relative humidity. Oil/liquid crystal/water system was proved to have higher ability to hold water in comparison with oil/water system. The results indicated that oil/liquid crystal/water system was of benefit to rheological properties creme type hair care products.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 1999년도 IFSCC . ASCS 학술대회 발표 논문
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• pp.123-131
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• 1999

Liquid crystal known as a rheological barrier to coaleseence of oil dorplets. increases. emulsion stability, water-holding capacity and promotes active material penetration to skin. Some investigation for its rheological characteristics have been reported but its relations to consumer perception have been rarely published. In this study oil/water emulsion and oil/liquid crystal/water systems were manufactured using the same composition of Behenyltrimethylammonium chloride/Cetostearyl alcohol/Lanolin oil. and rheological properties of each system were investigated with Cone and Plate rheometer. The formation of liquid crystalline phase was observed with polarized microscope and Differential Scanning Calorimeter. Continuous shear experiment, creep yield and water holding capacity were measured for oil/water and oil/liquid crystal/water systems. The results were compared with sensory evaluations. Oil/liquid crystal/water system showed higher viscosity at the same shear rate, higher viscoelasticity and higher yield stress than oil/water system. These properties were expected to show good spreadability and excellent richness without waxiness I hair care products of creme type. This expectation was consistent with the results of sensory experiments. Water-holding capacity was evaluated by measuring residual water of specimens at specific temperature and relative humidity, Oil/liquid crystal/water system was proved to have ability to hold water in comparison with oil/water system. The results indicated that oil/liquid crystal/water system was of benefit to rheological properties creme type hair care products.

• 공업화학
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• 제8권2호
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• pp.246-251
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• 1997

당류를 친수기로 한 슈크로오스 모노팔미테이트에 대한 3성분계 즉, 슈크로오스모노팔미테이트/알칸올/물계에서의 상거동을 각 조성에 따라 조사하였다. 미셀영역에서 여러 액정영역에 이르기까지 각 성분의 조성을 변화시키면서 정온 및 변온하에 여러 상의 구조를 온도조절기와 카메라가 부착된 편광현미경으로 비교 관찰하였다. 극성물질인 알칸올의 탄소수 증가에 따른 3성분계에서의 상거동을 관찰한 결과, 헥산올<옥탄올<데칸올 순으로 비교적 넓은 영역에서 비등방성의 여러 액정상이 존재하였으며, 이를 토대로 에멀젼이나 가용화계의 포뮬레이션에 적용할 수 있다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.197-199
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• 2007

Four banana-shaped compounds have beene synthesized introducing ester linking group into mesogenic unit, varying the central core with 1,6-, 1,7-, 2,3-, and 2,7-naphthylene units, and introducing the dodecyloxy group as the terminal flexible unit. All obtained compounds except one with 1,7-naphthylene unit were reversibly thermotropically liquid crystalline. The compound with 1,7-naphthylene unit could not form the mesophase due to its asymmetrical and sharp substitution angle. The compounds with 1,6- and 2,3-naphthylene units showed an antiferroelectric switchable smectic phase, which has been designated B2 phase. Interestingly, the compound with the 2,3-naphthylene unit showed the two mesophases of B2 and nematic phase.

• 공업화학
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• 제23권2호
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• pp.138-142
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• 2012

블루 안료 15 : 6이라 불리는 ${\epsilon}$ 결정상의 동프탈로시아닌(${\epsilon}$-CuPc)는 LCD 패널에서 청색화소를 제공하는 중요한 소재로써, 본 연구에서는 ${\epsilon}$-CuPc 시료를 ${\epsilon}$-CuPc 나노 입자를 seed로 이용하는 방법으로 여러 조건에서 합성하여 적합한 용매 및 온도조건 등을 규명하였고, 이를 미리 합성한 ${\alpha}$ 및 ${\beta}$ 결정상의 CuPc 시료들과 비교함으로써 ${\epsilon}$-CuPc 시료의 결정상, 결정 순도, 합성 수율 및 미세구조를 상호 비교 분석하였다. 시료들의 화학 구조 및 결정 구조는 푸레어 변환 적외선(FT-IR) 분광기 및 X선 회절 분석기(XRD)를 이용하여 각각 비교 분석하였다. 또한, 입자의 형상 및 크기는 주사 전자현미경(FE-SEM)으로 비교 분석하였고, 열적 특성은 열중량분석기(TGA)를 이용하여 비교 분석하였다.

• 문화기술의 융합
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• 제9권6호
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• pp.855-859
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• 2023

질산구리삼수화물염(copper(II) nitrate trihydrate) 수용액을 공업용 전분(starch)에 함침 시킨 전구체를 이용하여 산화구리(CuO) 나노 입자를 합성하였다. 주사전자현미경(SEM)을 통하여 질산구리삼수화물염 수용액이 함침된 전구체에 대한 구조를 분석하였고, 전구체에 대한 열처리 온도를 증가 시킴에 따라 생성되는 산화구리 입자의 입자 크기와 결정 구조를 X선회절분석법(XRD)과 주사전자현미경(SEM)으로 분석하였다. 분석 결과에 따르면, 전구체에서 유기물질이 완전히 열분해 되어지는 온도는 450-490℃이며, 열처리하는 온도가 증가함에 따라 생성되는 산화구리 입자의 크기와 결정성이 증가하는 것을 확인할 수 있었고, 또한 500-800℃에서 1시간씩 열처리하여 얻은 산화구리 입자의 크기는 100nm-2㎛인 것으로 나타났다. 하소 온도 400℃에서 산화구리 결정상이 형성되고, 800℃까지는 산화구리 단일상만 존재하며, 하소 온도의 증가에 따라 생성되는 입자의 크기가 커지는 것을 확인하였다.

• 한국세라믹학회지
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• 제53권3호
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• pp.325-331
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• 2016

Anatase particles of titanium dioxide were prepared from $TiCl_4$ aqueous solution by using an electro-dialysis [ED] process. For the preparation of an aqueous solution of $TiCl_4$ precipitates, $TiCl_4$ liquid frozen in ice was transferred to a neck flask and then hydrolyzed using deionized [DI] $H_2O$. During the hydrolysis of the $TiCl_4$ solution at $0^{\circ}C$, a slurry solution of $TiOCl_2$ was obtained and the color changed from red to orange. The ED process was applied for the removal of chlorine content in the slurry solution. Two kinds of hydrolyzed slurry solution with lower [$Ti^{4+}$] and higher [$Ti^{4+}$] were sampled and the ED process was applied for the samples according to the removal time of [$Cl^-$]. With de-chlorination, the solution status changed from sol to gel and the color quickly changed to blue. Finally, white crystalline powders were formed and the phase was confirmed by XRD to be anatase crystallites. The morphology of the hydrous titania particles in the solution was observed by FE-SEM. The hydrous titania particles were nano-crystalline, and easily coagulated with drying.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.256-256
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• 2013

Carbon nanotubes (CNT) / polyvinylidene fluoride (PVDF) piezoelectric composite films for nanogenerator devices were fabricated by spray coating method. When the CNT/PVDF mixture solution passes through the spray nozzle with small diameter by the compressed nitrogen gas, electric charges are generated in the liquid by a triboelectric effect. Then randomly distributed ${\beta}$ phase PVDF film could be re-oriented by the electric field resulting from the accumulated electrical charges, and might be resulted in extremely one-directionally aligned ${\beta}$ phase PVDF film without additional electric field for poling. X-ray diffraction patterns were used to investigate crystal structure of the CNT/PVDF composite films. It was confirmed that they revealed extremely large portion of the ${\beta}$ phase PVDF crystalline in the film. Therefore we could obtain the poled CNT/PVDF piezoelectric composite films by the spray coating method without additional poling process. Charge accumulation and resulting electric field generation mechanism by spray coating method were shown in Fig. 1. The capacitance of the CNT/PVDF films increased by adding CNTs into the PVDF matrix, and finally saturated. However, the I-V curves didn't show any saturation effect in the CNT concentration range of 0~4 wt%. Therefore we can control the performance of the devices fabricated from the CNT/PVDF composite film by adjusting the current level resulted from the CNT concentration with the uniform capacitance value.

• Korean Chemical Engineering Research
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• 제48권5호
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• pp.615-620
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• 2010

본 실험은 다섯 종류의 새로운 형태의 액정성 폴리우레탄을 4,4'-Bis(3-hydroxypropoxy)biphenyl (BP3)와 2,6-tolylene diisocyanate(2,6-TDI), 2,5-tolylene diisocyanate(2,5-TDI), 2,4-tolylene diisocyanate(2,4-TDI), 1,4-phenylene diisocyanate(1,4-PDI) 및 hexamethylene diisocyanate(HDI)의 중부가 반응에 의해 합성하였다. 단량체 BP3은 스멕틱상을 형성하였으며 HDI/BP3을 제외한 나머지 폴리우레탄에서는 모두 단방성 액정성을 나타내었다. 그러나 메틸 치환기를 가지고 있지 않는 1,4-PDI/BP3에서는 DSC 및 편광현미경에서도 액정상을 전혀 관찰할 수 없었다. 합성된 화합물의 구조는 FT-IR 및 $^1H$-NMR에 의해 확인하였으며, 그들의 열적 상전이온도 및 안정성들은 DSC, 편광현미경 및 x-선 회절에 의해 조사하였다.

• 한국진공학회지
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• 제22권6호
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• pp.306-312
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• 2013

화학적 증기증착(Chemical Vapor Deposition, CVD) 방법을 이용하여 단결정 Indium antimonide (InSb) 나노와이어를 $SiO_2$ wafer 위에 성장시켰으며, 성장된 InSb 나노와이어의 결정성과 조성비를 X-Ray Diffraction (XRD)과 Energy Dispersive x-ray Spectroscopy (EDS)의 측정을 통하여 확인하였다. 또한, 반응 source로 사용된 InSb 분말의 기상화(vaporization) 정도를 source container의 모형, 즉 open 및 close 시스템으로 변형하여 조절하였고 이렇게 성장된 InSb 나노와이어들의 구조적 특성을 주사전자현미경(Scaning Electron Microscopy, SEM)을 통하여 자세히 분석함으로써, 그들의 성장과정을 Vapor-Liquid-Solid (VLS) 및 Vapor-Solid (VS) 메커니즘으로 설명하였다. Open-boat를 사용하여 나노와이어를 성장시켰을 경우, close-boat 의 경우와 비교하여 합성된 나노와이어의 yield가 높았으며 나노와이어의 길이와 두께도 증가하는 현상이 관측되었다. 이러한 결과는, InSb source 의 기상화 정도가 close-boat에서 보다 open-boat에서 더욱 가속화되면서 공통적으로 일어나는 VLS 성장 이외에 VS 성장이 추가적으로 진행되어지기 때문으로 추측되어진다. 또한, 반응시간을 증가시켰을 때, 나노와이어의 두께가 증가하는 결과를 통하여 InSb 나노와이어의 성장에서 VS 메커니즘이 우세하게 작용하고 있음을 확인할 수 있었다.