• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2009년도 학술발표대회
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• pp.118-119
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• 2009

As the rapid development of the electronics, the demand for portable electronics and wireless sensors is growing faster, also with the increased needs of one material which can power it automatically, and then power the electrical devices. The piezoelectric effect of the PVDF material can be used for this. So in this paper, PVDF multilayer films were made for this aim. Make the PVDF / DMAc solution in the 10% concentration; use the spin coater technique to make films with the optimum process parameters: the spin rate is 1260rpm; the spin time is 70s; the dry temperature is 100$^{\circ}C$; the dry time is 30mins. And also, for obtaining the higher $\beta$-phase crystallinity, put the Ca(NH3)2.4H2O into the PVDF / DMAc solution system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.297-300
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• 1997

In this study, The PVDF thin film was fabricated on the one method of dry-process the physical vapor deposition method, applied electric field, and evaporation control in $\beta$-PVDF thin film preparation. A study on the electric-field-phase change of PVDF thin film in physical vapor deposition using the polymer deposition apparatus which are manufactured for oneself. In the analysis of Fourier-Transform Infrared spectra, according to increasing of electric field intensity, the 510$cm^{-1}$ / peak and 1273$cm^{-1}$ / peak which are showed in $\beta$-PVDF increase, on the contrary the 530$cm^{-1}$ / peak and 977$cm^{-1}$ / peak which are showed in $\alpha$-PVDF decrease.

• 폴리머
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• 제28권5호
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• pp.361-366
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• 2004

가해준 하중에 따라 폴리(비닐리덴 플루오라이드) (PVDF) 필름에서 발생하는 전압을 측정하며 분포형 촉각센서로서의 특성을 연구하였다. PVDF 필름에 전기장과 온도를 달리하면서 극화 (poling)의 변화를 주었고 이에 따른 필름의 압전성을 나타내는 $\beta$-결정상의 피크를 FT-IR. DSC와 XRD를 사용하여 확인하였다. 본 연구에서 사용된 온도와 전압의 영역에서는 극화 온도가 증가함에 따라 그리고 극화 전압이 증가함에 따라 $\beta$-결정상은 증가하였으며, 이에 따라 유전상수가 역시 증가하였다. 8$\times$8어레이 (array)로 제작된 촉각센서에 힘을 가하여 극화에 따른 전압 발생량을 측정한 결과, 극화가 많이 된 시편의 경우 높은 전압이 발생하는 것을 확인하였다.

• Composites Research
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• 제33권1호
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• pp.19-24
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• 2020

본 연구에서는 Poly(vinylidene fluoride) (PVDF) 필름 제작 과정 중 마이크로웨이브 처리 과정을 도입하여 β 결정성 향상에 어떠한 영향을 미치는지 분석하였다. 또한, 나노 입자 보강제로써 금속산화물인 TiO₂를 혼합하여 PVDF 복합재료 필름을 만들어, 전기적 음성도 차이로 인한 반데르발스 힘을 통해 β 결정 형성을 추가적으로 향상시키려고하였다. FTIR과 XRD 분석을통하여해당필름시편들에대해결정화도(Crystallinity) 및결정성(Crystalline)을 분석하였다. 이러한 분석 결과를 바탕으로, 용매 증발 과정 중 마이크로웨이브 처리 과정이 PVDF 필름의 결정화도를 높여주는 것을 확인하였고, 추가적인 연신(Stretching) 공정을 통해 α 결정에서 β 결정 변화(Crystalline phase change)가 발생함으로써 결과적으로 더 많은 β 결정성을 나타내었다. 그리고 금속산화물을 넣은 PVDF 복합재료 필름이 Neat PVDF 필름보다 상대적으로 더 높은 β 결정성을 나타내는 것을 확인하였다.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.478-485
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• 2018

The effect of reduced graphene oxide (RGO) addition on the dielectric and piezoelectric behavior of the polyvinylidene fluoride (PVDF) films was studied. Dielectric constant increased by four times and piezoelectric coefficient also increased twice by the addition of RGO in the PVDF films. Based on capacitance-voltage and ellipsometry measurements and the Kramers-Kronig transformation, it is concluded that the enhanced dielectric and piezoelectric properties of the PVDF/RGO films resulted from the increased orientational polarization due to a phase transition from nonpolar crystalline ${\alpha}$ phase to polar crystalline ${\beta}$ phase in the PVDF structure.

• 한국전기전자재료학회논문지
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• 제26권8호
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• pp.620-623
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• 2013

The carbon nanotube / poly-vinylidene fluoride (CNT/PVDF) composite films for the nano-generator devices were fabricated by spray coating method using the CNT/PVDF solution, which was prepared by adding PVDF pellets into the CNT dispersed N-Methyl-2-pyrroli-done (NMP) solution. The flexible CNT/PVDF composite films were investigated by the scanning electron microscopy, which revealed that the CNTs were uniformly dispersed in the PVDF matrix and thickness of the films was approximately $20{\mu}m$. Fourier transform infra-red spectra were used to investigate crystal structure of the as-spray-coated CNT/PVDF films, and we found that they revealed extremely large portion of the ${\beta}$ phase PVDF. The capacitance of the CNT/PVDF films increased by adding CNTs into the PVDF matrix, and finally saturated. However, the resistance didn't show any saturation effect in the CNT concentration range of 0~4 wt%. Finally, the resulting nano-generator devices revealed reasonable current output after given mechanical stress.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.76-79
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• 2000

The 3$\mu\textrm{m}$-thick PVDF (Polyvinyiidene fluoride) thin film have been prepared using physical vapor deposition with electric field, and its FT-IR specrum, dielectric property and electric conduction phenomenon have been investigated. Since the characteristic peaks ate detected at 509.45 and 1273.6〔cm〕 in the FT-IR spectrum, we are confirmed that the ${\beta}$ -phase is dominant in the PVDF thin film. In the results of dielectric properties, the PVDF thin film shows anomalous dispersion, i.e. gradual decrease of dielectric constant with increase of frequency, and also that the dielectric absorption point changes from 200Hz to 7000Hz with increasing temperature of thin film, which is consistent with the Debye's theory. The activation energy (ΔH) obtained from temperature dependence of dielectric loss is 21.64 ㎉/㏖. We confirm that the electric conduction mechanism of PVDF thin film is dominated by ionic conduction by investigating the dependence of the leakage current of the thin film on the temperature and the electric field.

• 멤브레인
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• 제31권6호
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• pp.434-442
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• 2021

Poly(vinylidene fluoride) (PVDF) 막은 내구성 및 열적·화학적 안정성 등의 물성은 우수하나 소수성이 커서 수투과도가 낮고 단백질 및 유기물에 의한 막오염이 쉽게 발생한다. 본 연구에서는 PVDF 막의 내오염성을 개선시키고자 바이오 기능성 물질인 𝛽-cyclodextrin (𝛽-CD)을 PVDF 막 구조 내에 분산 함침시킨 PVDF/𝛽-CD 혼합기질 비대칭막을 상변환법을 통해 제조하고, 𝛽-CD 함침량에 따른 순수 투과 유속(PWF) 측정과 BSA 용액을 대상으로 한 막여과 실험을 수행하여 내오염성 특성을 평가하였다. 이 결과 PVDF 고분자 매질 내에 𝛽-CD를 함침시키면 막의 친수성을 증가시켜 접촉각을 감소시키고 이로 인해 내오염성을 향상시킬 수 있었다. 𝛽-CD 함침량이 2 wt%인 도프용액을 사용하여 제조된 PVDF/𝛽-CD 혼합기질 비대칭막의 PWF는 64 L/m²·h, BSA 배제도는 95%를 나타내었으며, 𝛽-CD를 첨가하지 않고 제조된 pristine PVDF 막에 비해 투과 유속 향상성이 최대 80%에 달해 𝛽-CD를 첨가시킴으로서 PVDF 막의 내오염성을 증가시킬 수 있었다.

• 한국진공학회지
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• 제8권3A호
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• pp.187-193
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• 1999

In this study, PVDF thin films which show the excellent piezoelectricity and pyroelectricity, are prepared by PVD (physical vapor deposition) method, and thir electrical conduction phenomena for analyses of the electrical conduction mechanism and TSC (Thermally Stimulated Current) for identification of the behavior of conductive carriers are investigated. As a result of FT-IR(Fourier Transform Infrared Spectroscopy) spectra, the crystalline phase transforms $\alpha$ type into $\beta$ type with increasing electric field. From XRD (X-Ray diffraction) analyses patterns, the degree of crystallinity increases from 49.8% to 67%, as the substrate temperature increases from $30^{\circ}C$ to $80^{\circ}C$. As a result of electrical conduction phenomena, the electrical conduction mechanism of PVDF thin films is identified as ionic conduction mechanism. From TSC analyses, there are three peaks as P1, P2, P3 with increasing temperature, and with increasing substrate temperature, the peak temperature of TSC increases and the peak intensity of TSC decreases.

• 멤브레인
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• 제33권1호
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• pp.13-22
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• 2023

리튬 금속 기반 전극의 높은 용량에도 불구하고, 제어가 어려운 덴드라이트 성장은 낮은 쿨롱 효율, 안전 문제를 야기해, 리튬금속 배터리의 상용화를 제한한다. 본 연구에서는 압전 복합체인 BaTiO₃/PVDF (BTO@PVDF) 기반 보호층을 리튬금속에 코팅, 덴드라이트에 의한 부피팽창으로 발생한 변형을 분극을 이용하여, 리튬 금속 전극의 안정성 및 성능을 향상하고자 한다. 이를 통해, 균일한 리튬이온의 증착이 가능해졌으며, BTO@PVDF 전극은 100 사이클 동안 약 98.1% 이상의 쿨롱 효율을 나타내었다. 또한, CV를 통해 향상된 리튬이온의 확산계수(D_Li+) 증가를 보였으며, 본 연구에서 제시된 전략은 리튬 금속 전극의 성능 향상에 새로운 길을 나타내준다.