• The Journal of Advanced Prosthodontics
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• 제5권2호
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• pp.75-83
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• 2013

PURPOSE. Maxillofacial silicone elastomer is usually colored intrinsically with color pigments to match skin colors. The purpose of this study was to investigate the color stability of a maxillofacial silicone elastomer, colored with a thermochromic, color changing pigment. MATERIALS AND METHODS. Disc-shaped maxillofacial silicone specimens were prepared and divided into 3 groups: a conventionally colored control group, one group additionally colored with 0.2 wt% thermochromic pigment, and one group with 0.6 wt% thermochromic pigment. Half of the surface of each specimen was covered with an aluminium foil. All of the specimens were exposed to UV radiation in 6 hour cycles over 46 days. In between the UV exposures, half of the specimens were stored in darkness, at room temperature, and the other half was stored in an incubator, at a humidity of 97% and a temperature of $+37^{\circ}C$. Color measurements were made with a spectrophotometer and registered according to the CIELAB $L^*a^*b^*$ color model system. The changes in $L^*$, $a^*$ and $b^*$ values during artificial aging were statistically analyzed by using paired samples t-test and repeated measures ANOVA. P-values <.05 were considered as statistically significant. RESULTS. The UV exposure resulted in visually noticeable and statistically significant color changes in the $L^*$, $a^*$ and $b^*$ values in both of the test groups containing thermochromic pigment. Storage in the incubator lead to statistically significant color changes in the $a^*$ and $b^*$ values of the specimens containing thermochromic pigment, compared to those stored at room temperature. CONCLUSION. The specimens containing thermochromic pigment were very sensitive to UV radiation, and the thermochromic pigment is not suitable, as such, to be used in maxillofacial prostheses.

• Journal of the Optical Society of Korea
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• 제17권2호
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• pp.168-171
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• 2013

A reflective flexible display was fabricated by placing a thermochromic pigment on a polyethylene naphthalate (PEN) substrate coated with an indium tin oxide (ITO) film, and its thermo-optical characteristics were investigated. The reflective thermochromic display showed good image quality with a reflectance of approximately 65%. As a flexible display, the display showed reliability without damage to the image even after the display was bent strongly. The reflective display cell exhibits continuously the gray level according to the temperature controlled by applied voltage. This low cost display is expected be used in outdoor poster applications where information needs to be presented clearly.

• Journal of the Optical Society of Korea
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• 제17권5호
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• pp.428-432
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• 2013

This research presents a flexible reflective thermochromic display (TCD) comprised of thermochromic pigments and a patterned indium tin oxide (ITO) film coated on a polyethylene naphthalate (PEN) substrate, and the display's thermo-optical characteristics. The display showed maximum red, green, and blue reflectances of 30%, 38%, and 29%, respectively. Furthermore, the display exhibited a continuous grey color when the temperature was changed continuously. As a flexible display, the display showed reliable thermo-optical performance without image damage even when highly bent. We expect the proposed TCD will be used in outdoor information display applications where low cost is a key factor.

• 펄프종이기술
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• 제43권5호
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• pp.11-16
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• 2011

This study was aimed to apply thermochromic and photochromic pigments to coating color and to develop a speciality functional coated layer. Two special pigments were added to a conventional coating color. The effects of the special pigments on coating color properties such as water rerention, low-shear viscosity were evaluated. Also the color changes of coated paper was observed under various circumstances. The results showed that the special pigments didn't influence the coating color properties. The coated paper with the special pigments showed four different colors, under various circumstances, implying that thermochromic and photochromic pigments can be used to produce a security paper.

• 한국염색가공학회지
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• 제30권1호
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• pp.1-8
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• 2018

In the present study, three morpholine substituted crystal violet lactone (CVL) have been synthesized to monitor the thermochromic property. This work is explaining the role of substituent on the lactone ring. The methyl substituents induced greater chromic effects than the chloro substituents. Furthermore, the three-component mixtures that contained CVL, bisphenol-A, and methyl stearate were used to analyse the thermochromic effect of the CVLs as bulk samples with various temperature. The thermochromic properties of the CVLs were evaluated using solid-state UV-Vis and FT-IR spectroscopic techniques. Finally, one of the synthesized CVL has been successfully converted into the form of a test paper similar to pH paper for use as thermal indicators.

• 한국세라믹학회지
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• 제35권1호
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• pp.11-16
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• 1998

$VO_2$ thin films have been prepared on borosilicate glass substrate using alkoxide method to characterize the effects of fabricating factors on thermochromic performance. The gel films formed by spin coating were converted to $V_2O_5$ phase during oxidizing heat-tratment and the $VO_2$ phase were formed by reducing heat-treatement. The thermochromic switching properties of $VO_2$ thin films are strongly affected by the crystal phase and microstructure and those could be controlled by reducing heat-treatment conditions. The ther-mochromic switching characteristics of $VO_2$ thin films synthesized were measured at IR (2.5$\mu\textrm{m}$) as the transition temperature of $63^{\circ}C$ the transition width of $3.6^{\circ}C$and the maximum and minimum transmittance of 84% and 14% respectively.

• 한국융합학회논문지
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• 제12권11호
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• pp.291-299
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• 2021

최근 도시 지역의 고밀도화 및 고층화에 의한 환경 문제로 인해 도심 지역의 공기 유동에 대한 관심이 높아지고 있으며, 이에 따라 건축물의 적절한 형상 및 배치 설계가 요구되고 있다. 본 연구에서는 온도에 따른 색 변화 특성을 갖는 열변색성 염료를 이용하여 건물 주위의 공기 유동 경향을 관찰할 수 있는 실험 방법을 제안하고자 한다. 열변색성 염료는 특정 온도에 대해서만 색이 변하는 특성 때문에 온도 변화를 정밀하게 관찰하기에는 한계가 있지만 실험 모델 및 장비 구성이 용이하고 실험에 소요되는 시간이 짧다는 장점을 가지고 있다. 따라서 본 연구에서는 단순 형상 모델에 대한 CFD 해석을 통하여 건물 주위의 바람에 의한 공기 유동 경향을 분석한 후 열변색 실험 결과와 비교함으로써 제안된 실험 방법의 유용성을 검토하였다. 이러한 실험의 결과로서 열변색성 염료의 특성을 이용하여 도심 건물에 의해 발생되는 박리풍과 와류의 형성 영역을 관찰할 수 있었으며 제안된 방법이 건축물 설계 및 도시 계획에 유용하게 활용될 수 있다는 것을 확인하였다.

• 한국화재소방학회논문지
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• 제22권5호
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• pp.61-66
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• 2008

본 연구에서는 특정물질의 과열로 인한 이상 상태를 조기에 감지하여 화재 및 폭발로의 전이 위험성을 사전에 예방할 수 있는 방법 중 하나로 열변색 색소를 유효성분으로 한 겔성형체를 제조하여 그 특성을 평가하였다. 또한 과열감지용 대상물에 대한 적용성을 확대하기 위하여 성형체는 원료물질의 종류와 함량, 그리고 제조방법에 따라 점탄성형과 도포형의 2가지로 제조하였다. 변색성 시험, 점도 특성, 변색 개시시간, FT-IR 분석을 수행한 결과 이상 조건을 효과적으로 감지하여 변색 기능을 나타낼 수 있는 물질이 제조되어 다양한 응용이 가능할 것으로 사료된다.

• 대한기계학회논문집B
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• 제24권2호
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• pp.188-194
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• 2000

Thermochromic liquid crystal reflect a unique color at even temperature. Therefore, they have been successfully applied to non-intrusive heat transfer research. Hue capturing method is widely used in the quantitative measurement from the TLC image. However it is affected by several measurement conditions. The distances of camera and light source have little influence on the color, but the value of hue is seriously affected by the measurement angle. In this study, the hue capturing method is improved by considering the effect of measurement angle. This improved calibration method can diminish the misreading of temperature caused by curvature of test surface.

• 공업화학
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• 제26권4호
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• pp.427-431
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• 2015

본 연구에서는 열-변색 소재로 잘 알려진 이산화바나듐($VO_2$) 분말을 $V_2O_5$ 분말과 옥살산 수화물로부터 여러 조건에서 수열합성과 하소공정을 통하여 제조하였다. 제조된 시료들의 화학적 구조, 결정구조 및 열적 특성들은 FE-SEM, XRD, XPS 및 DSC를 이용하여 분석하였다. 또한, 필름 시편들의 분광학적 및 열변색 특성은 제조된 분말 시료들을 볼밀링하여 50 nm 이하로 분산시켜 제조된 졸로부터 박막필름을 제작하여 UV-Vis-NIR 분광기를 이용하여 분석하였다. $VO_2$ 시료의 하소처리 온도를 증가시키면, 입자들의 크기가 증가함에 따라 시료의 상전이온도가 약 $40^{\circ}C$에서 $70^{\circ}C$로 증가하는 경향을 나타내었다.