• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2002년도 봄 학술발표회 논문집
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• pp.183-186
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• 2002

Polymer composites with carbon nanotubes have recently been investigated for improving certain properties i.e., electrical, optical and mechanical properties[1-3]. Kymakis et. al. have reported the electrical and optical properties of single wall carbon nanotube-poly(3-octylthiophene) composites[4]. Polyurethane dissolved in dimethylformanide (DMF) were electrospun by Demir et. al.[5]. (omitted)

• 멤브레인
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• 제24권2호
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• pp.107-112
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• 2014

Poly (vinylidene fluoride) (PVDF)의 소수성 중공사막 표면에 계면중합하여 복합막을 제조하였다. Piperazine (PIP)과 trimesoyl chloride (TMC)의 농도변화, polyethylene glycol (PEG)의 함량변화에 따라 막을 제조하였으며, 막의 특성 평가를 위해 100 ppm의 NaCl, $CaSO_4$, $MgCl_2$ 용액과 NaCl과 $CaSO_4$를 혼합하여 제조한 300 ppm의 공급액에 대한 막의 투과도와 배제율을 알아보고자 하였다. TMC를 사용하여 계면중합하였을 때 막의 투과도와 배제율이 가장 높게 나타났으며, 0.1~1 wt%로 TMC 농도를 변화시켜 가며 실험을 수행한 결과 0.1 wt%일 때 NaCl 100 ppm에 대해 투과도 48.3 LMH ($L/m^2{\cdot}hr$)와 배제율 59%로 가장 높은 값을 나타내었다. 또한, 투과도를 향상시키기 위해 annealing처리와 piperazine에 PEG를 첨가하여 실험을 수행하였다. 실험결과 처리하지 않은 막에 비해 투과도는 전체적으로 향상되는 모습을 나타냈지만 배제율이 감소하는 경향을 나타내었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.714-717
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• 2007

In this study, a novel actuator was developed by employing the newly-synthesized ionic networking membrane (INM) of poly (styrene-alt-maleic anhydride) (PSMAn)-incorporated poly (vinylidene fluoride) (PVDF). Based on the same original membrane, various samples of INM actuator were prepared through different reduction times with the electroless-plating technique. The as-prepared INM actuators were tested in terms of surface resistance, platinum morphology, resonance frequency, tip displacement, current and blocked force, and their performance was compared to that of the widely-used traditional Nafion actuator. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) revealed that much smaller and more uniform platinum particles were formed on the surfaces of the INM actuators as well as within their polymer matrix. Although excellent harmonic response was observed for the newly-developed INM actuators, this was found to be sensitive to the applied reduction times during the fabrication. The mechanical displacement of the INM actuator fabricated after optimum reduction times was much larger than that of its Nafion counterpart of comparable thickness under the stimulus of constant and alternating current voltage.

• 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.

• 한국전기전자재료학회논문지
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• 제27권11호
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• pp.740-745
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• 2014

ZnO nanowires were grown by hydrothermal synthesis process and piezoelectric poly vinylidene fluoride (PVDF) was then coated on top of the ZnO-nanowires by spray-coating technique. The composite layer of ZnO-nanowires/PVDF was applied to an energy harvesting device based on piezoelectric-conversion mechanism. A defined mechanical force was given to the nanogenerator device to evaluate their electric power generation characteristics, where output current density and voltage were examined. Electric power generation property of the ZnO-nanowires/PVDF based nanogenerator device was compared to that of the nanogenerator device with ZnO-nanowires as single active layer. Effect of the ZnO-nanowires on improvement of power generation was discussed to examine its feasibility for the nanogenerator device.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.224-225
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• 2005

The microstrip patch antenna with PVDF (poly vinylidene fluoride) substrate, were experimentally studied at frequency 6 GHz. During the design of the essential elements of microstrip antenna, EM simulation tool Ensemble V 7.0 is used. We observed the resonant frequency by DC appled electric field in a microstrip patch antenna. This research has been made as an electronically tunable microstrip antenna, taking advantage of the voltage control dielectric substrate and piezoelectric properties substrate. We discuss the effect of substrates, electric field and piezoelectric phenomena in the PVDF microstrip antenna. The antenna frequency can be changed by varying the applied dc voltage. In this paper, we propose, a new technique to agile frequency of the microstrip antenna by using the PVDF piezoelectric substrate.

• 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.

• 대한방사선기술학회지:방사선기술과학
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• 제23권2호
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• pp.33-37
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• 2000

The authors fabricated ultrasonic transducer with PVDF[poly(vinylidene fluoride)] piezoelectric polymer film. When impulse waves were applied to the PVDF ultrasonic transducer, the dependence of the response properties on the backing material with copper was investigated through not only theoretical calculations using Mason's equivalent circuit but also experimental measurements. The experimental pulse response properties agree with those of the theoretical calculations and the pulses were shorter than those for a PZT transducer. If such short-pulse properties are used in an medical ultrasonic image diagnosis apparatus, the resolution of the apparatus will be improved. When the insertion loss was calculated theoretically to the PVDF ultrasonic transducer, the frequency characteristics of its showed wideband frequency.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.252-253
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• 2005

The dielectric relaxation properties of $^{60}Co$ gamma-ray irradiated Poly(vinylidene fluoride) (PVDF) containing various antioxidants have been investigated for radiation degradation. Cole-Cole's circular arcs were induced from the results of temperature and frequency dependency of dielectric properties with radiation dose. The magnitude of polarization of PVDF was decreased by adding antioxidants. The values of dielectric relaxation intensity calculated by using the Cole-Cole's circular arcs showed a certain tendency for radiation degradation.

• Membrane and Water Treatment
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• 제1권3호
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• pp.215-230
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• 2010

Poly(vinylidene fluoride-co-hexafluoropropylene), PVDF-HFP, hollow fiber membranes were prepared by the dry/wet spinning technique using different polyethylene glycol (PEG) concentrations as non-solvent additive in the dope solution. Two different PEG concentrations (3 and 5 wt.%). The morphology and structural characteristics of the hollow fiber membranes were studied by means of optical microscopy, scanning electron microscopy, atomic force microscopy (AFM) and void volume fraction. The experimental permeate flux and the salt (NaCl) rejection factor were determined using direct contact membrane distillation (DCMD) process. An increase of the PEG content in the spinning solution resulted in a faster coagulation of the PVDF-HFP copolymer and a transition of the cross-section internal layer structure from a sponge-type structure to a finger-type structure. Pore size, nodule size and roughness parameters of both the internal and external hollow fiber surfaces were determined by AFM. It was observed that both the pore size and roughness of the internal surface of the hollow fibers enhanced with increasing the PEG concentration, whereas no change was observed at the outer surface. The void volume fraction increased with the increase of the PEG content in the spinning solution resulting in a higher DCMD flux and a smaller salt rejection factor.