• 한국안전학회지
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• 제18권3호
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• pp.60-63
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• 2003

For the increase the charge stability of teflon electrets for used at uncomfortable industrial circumstances with high temperature or humidity, We made an investigation into double layer effect of teflon electrets. Teflon AF film was spincoated on FEP film and then the charge storage property of AF/FEP dual film was investigated to be compared with FEP film. It was found that the AF/FEP dual film has higher surface potential than FEP film on the repeated charging and annealing process. It seems that AF/FEP dual film has higher thermal stability than FEP film through TSC measurement. If the investigations of the double layer effect of Teflon film carried out more closely with it's molecular structures and surface conditions, it may be effectively improved the stability of charge storage.

• 한국전기전자재료학회논문지
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• 제16권8호
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• pp.693-699
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• 2003

To improve thermal stability of Teflon FEP which is the most widely used materials for electret application, Teflon AF film of 1 $\mu\textrm{m}$ thick was spin coated on FEP film and the charge storage properties were investigated. The surface potential depend on aging temperature. Thermal Stimulated Current(TSC), Atomic Force Microscopy(AFM), and Fourier Transform-Infrared Spectroscope(FT-lR) measurements were carried out. It is shown that the AF/FEP dual film have more higher electrical property and thermal stability than that FEP film have caused by charge stored at interface of AF and FEP.

• Journal of Korean Society for Atmospheric Environment
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• 제20권E1호
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• pp.35-41
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• 2004

Aerosol wall loss is an important factor affecting smog chamber experiments, especially with chambers made of Teflon film. In this work, the aerosol wall loss was investigated in 2.5 and $5.8-m^3$ cubic-shaped Teflon film chambers filled with ambient air. The natural change in the particle size distribution was measured using a scanning mobility particle sizer in a dark environment. The rate of aerosol wall loss was obtained from the deposition theory suggested by Crump and Seinfeld (1981). The measured rates of aero-sol wall loss were In a good agreement with the theoretical and experimental values given by McMurry and Rader (1985), implying that the electrostatic effect enhances particle deposition on the chamber wall. The significance of aerosol wall loss correction was demonstrated with the photochemical reaction experiments using the ambient air.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.539-540
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• 2006

In this paper, We examine that characteristics of formative electret with polymer film and electric charge storage using grid corona discharge. compound polymer of fluorine resin used for material in electret because of high electric charge accumulation, excellent electrical and physical characteristic. All experiments were carried out with circular samples of $Teflon^(R)FEP$ film, 12.5[${\mu}m$] thick. As experiment variables, we used voltage, electrode thickness, discharge electrode gap, and discharge time. According to this variables, we studied on characteristics of formative electret and electric charge storage. Additionally we make a comparative study of the result between the grid corona discharge and needle electrode discharge.

• 한국전기전자재료학회논문지
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• 제27권11호
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• pp.730-735
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• 2014

In this study, the temperature characteristics of electrostatic capacity and dielectric loss for the sample of Teflon film which is degradated at the $120^{\circ}C{\sim}200^{\circ}C$ temperature range in the oven for 10 hours has been measured in through the applied frequency range of 0.1 kHz~4,800 kHz at temperature of $50^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $170^{\circ}C$. Also, in the same conditions, the frequency characteristics of electrostatic capacity and dielectric loss for the sample of Teflon film has been measured in through the applied temperature range of $30^{\circ}C{\sim}70^{\circ}C$ on setting frequency of 0.1 kHz, 1 kHz, 10 kHz, 100 kHz. The results of this study are as follows. When the frequency range of 0.1 kHz~4,800 kHz applied to the sample of Teflon film, the electrostatic capacity has been measured at the temperature of $50^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $170^{\circ}C$. Through this measurement, it found that the electrostatic capacity decreased with increasing temperature. Regarding this result, may be it is because the electromagnetic coupling is degraded by thermal degradation. When the sample of Teflon film heated at $280^{\circ}C$ for 10 hours in oven, the dielectric loss has changed from unstable status to stabilizing status with increasing the degradation temperature in the $120^{\circ}C$, $160^{\circ}C$, $200^{\circ}C$ range. In this measurement, the two spectrums of dielectric loss appeared. It considers that this spectrum of dielectric loss appeared in 300 Hz is caused by the molecular motion of the C-F or OH group. Through this study, It found that the electrostatic capacity decreased with increasing frequency and temperature, and there is no change in dielectric loss, although the frequency increases.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.269-271
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• 2004

In this report, high-performance organic light-emitting diodes (OLEDs) with polytetrafluoroethylene (Teflon) buffer layer are demonstrated. Compared with conventional buffer layer, copper phthalocaynine (CuPc), Teflon film shows lower absorption in the wavelength from 200nm to 800nm The OLEDs with Teflon and CuPc buffer layer were fabricated under same conditions, and the device performances were compared. The results indicate that when the thickness of Teflon is 1.5nm, the performance of OLEDs is greatly enhanced with an efficiency of 9.0cd/A at the current density of 100mA/$cm^2$, while the device with an optimized 30-nm-thick CuPc buffer layer only shows an efficiency of6.4cd/A at the same current density.

• 한국진공학회지
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• 제6권1호
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• pp.69-76
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• 1997

순간 증착법으로 $Bi_{0.5}Sb_{1.5}Te_3$(p형)와 $Bi_2Te_{2.4} Se_{0.6}$(n형) 박막을 제조하여 두께와 어닐 링 조건에 따른 Seebeck 계수, 전기전도도, carrier 농도 및 이동도, 열전도도, 성능지수의 변화 등 열-전기적 특성을 조사하였다. 473K에서, 1시간 진공 열처리한 결과 p형과 n형의 성능지구는 각각 $1.3{\times}10^{-3}K^{-1}$ 및 $0.3{\times}10^{-3}K^{-1}$으로 향상되었으며 두께에 크게 의존하지 않았 다. 이런 성질을 갖는 열전 박막을 소자화한 박막 온도 센서를 유리와 Teflon기판 위에 제 조하였으며, 이들의 온도 변화에 대한 열기전력, 민감도 및 시간 상수 등 센서 특성을 측정 하였다. p 및 n형의 leg 폭 1mm$\times$길이 16mm인 박막 온도 센서의 경우, Teflon 기판일 때 좋은 성능을 나타내었으며, 민감도는 2.91V/W, 시간 상수는 28.2초이었다.

• 한국재료학회지
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• 제15권4호
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• pp.271-274
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• 2005

We investigated the crystalline and electrical properties of ZnO thin films for transparent electrode as a function of the oxygen pressures during the deposition. The ZnO thin films were deposited on a flexible teflon substrates by the pulsed laser deposition. From the X-ray diffraction, ZnO films showed c axis oriented ZnO(0002) crystal structure. The FWHM (full width at half maximum) values decreased from $0.51^{\circ}\;to\;0.34^{\circ}$ as the oxygen pressure increased from 0.1 mTorr to 10.0 mTorr showing the improvement of crystallinity. The resistivity and hall mobility of ZnO film deposited at the oxgen pressure of 0.1 mTorr at $200^{\circ}C$ was about $5\times10^{-4}\Omega{\cdot}cm\;and\;20cm^2/V{\cdot}s$, respectively. The optical transmittance of the ZnO films on flexible teflon substrate was found to be above $85\%$.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.1882-1887
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• 2007

In the present experimental study, the effect of interfacial tensions on pressure drop of air-water two-phase flow in round mini-channels was investigated. A glass (highly wettable) tube and a Teflon (poorly wettable) tube, both in 350 mm length but 1.8 mm and 1.59 mm in inner diameters each, were used for the tests. All the experiments were performed only in the plug flow regime, confirmed by visualization. In the glass tube, the gas plugs were surrounded by the liquid film along the inner periphery. On the other hand, the inner wall remained dry at the gas portion in the Teflon tube. The pressure drop of the plug flow in the Teflon tube without the liquid film) appeared much larger than in the glass tube (with the liquid film) due to dissipation of energy by movement of the wetting lines. In this paper, various correlations on the two-phase pressure drop of plug flows were compared and a modified correlation was proposed, taking account of the surface wettability.

• 마이크로전자및패키징학회지
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• 제7권1호
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• pp.35-40
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• 2000

Teflon-like fluorocarbon thin film was deposited on various substrates by vapor deposition using PFDA (perfluorodecanoic acid). The fluorocarbon films were characterized by static/dynamic contact angle analysis, VASE (Variable-angle Spectroscopic Ellipsometry) and AFM/LFM (Atomic/Lateral Force Microscopy). Based on Lewis Acid/Base theory, the surface energy ($S_{E}$) of the films was calculated by the static contact angle measurement. The work of adhesion (WA) between de-ionized water and substrates was calculated by using the static contact data. The fluorocarbon films showed very similar values of the surface energy and work of adhesion to Teflon. All films showed larger hysteresis than that of Teflon. The roughness and relative friction force of films were measured by AFM and LFM. Even though the small reduction of surface roughness was found on film on $SiO_2$surface, the large reduction of relative friction farce was observed on all films. Especially the relative friction force on TEOS was decreased a quarter after film deposition. LFM images showed the formation of "strand-like"spheres on films that might be the reason far the large contact angle hysteresis.