대두종자의 polymer coating 연구 1 : polymer coating 종자의 conductivity 차이

李成春,J. S. Burris 韓國作物學會 1994 Korean journal of crop science Vol.39 No.2

Polyme coating 종자의 환경적응성을 구명하기 위한 일환으로 콩 종자에 10종의 polymer를 coating하여 각 coating polymer별 conductivity, 발아력, 수분흡수력을 조사하였던 바 그 결과를 요약하면 다음과 같다. 1. Conductivity는 polymer coating한 종자가 coating하지 않은 종자보다 높았으며, 가장 높았던 polymer는 waterlock이었다. 2. Conductivity는 침종 후 시간이 경과할 수록 높아졌고, 100립중이 무거울 수록 높았다. 3. 수확년도가 오래된 종자의 conductivity가 당년에 수확한 종자보다도 높게 나타났다 4. 수분흡수 정도는 coating polymer에 따라 각각 달랐는데 daran 8600은 질이 떨어지는 종자에서는 수분흡수를 크게 저 해하였다. 5. Coating polymer 중 waterlock, captan, klucel, sacrust 등은 발아율을 상승시켰고, daran 8600은 발아율을 저하시켰으며 나머지 polymer는 품종에 따라 각각 달랐고 그 정도는 질이 떨어지는 종자에서 훨씬 컸다. 6. Polymer의 특성에 따라 수분흡수를 저해하거나 조장하였다. These experiment were conducted to evaluate the environmentally acceptable polymers, and 10 polymers were used in these study, and to investigate conductivity, germination percentage, water uptake of polymeric coating soybean seed. The conductivity of polymeric coating seed is higher than that of none coating seed and the highest conductivity was obtained with waterlock coating seed among the 10 polymer coating seed. As the soaking time was long, the conductivity was increased. The conductivity of large seed was higher than that of small seed, and that of long period storage seed was higher than that of short period storage seed. The effects of seed coating polymers on uptake water were various, and daran 8600 inhibited uptake water of low quality seed. The waterlock, captan, klucel and sacrust was rised germination percentage, and daran 8600 was declined germination percentage, and the effect of coating polymers on germination percentage of low quality seed was higher than that of high quality seed.

Fabrication of conductive overcoat layer based on hybrid composites to protect flat conductive films

이진근,조원석,조한결,김영노,이홍주,김중현 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

Conductive polymers are attracting attention as promising next-generation materials due to their various advantages such as flexibility, transparency and price competitiveness. However, it has difficulty in practical application due to low physical stability such as heat resistance and water resistance. Therefore, we propose a method of overcoat a layer prepared by hybrid composites on a flat conductive film coated on a substrate to improve the physical stability of conductive polymer. This layer improves stability and hardness by forming a network structure through the combination of silane coupling agent and organic polymer. However, since this layer has an insulating property, it is impossible to move the current through the upper contact after application. Therefore, a small amount of conductive polymer PEDOT:PSS was added to provide conductivity. As a result, a flexible, transparent, conductive overcoat layer having high hardness and stability was manufactured.

Study on lowering the percolation threshold of carbon nanotube-filled conductive polypropylene composites

Park, Seung Bin,Lee, Moo Sung,Park, Min 한국탄소학회 2014 Carbon Letters Vol.15 No.2

Conductive polymer composites (CPCs) consist of a polymeric matrix and a conductive fil-er, for example, carbon black, carbon fibers,graphite or carbon nanotubes (CNTs). The criti-cal amount of the electrically conductive fillernecessary to build up a continuous conductive network, and accordingly, to make the material conductive; is referred to as the percolation threshold. From technical and economical viewpoints, it is desirable to decrease the conduc-tive-fillerpercolation-threshold as much as possible. In this study, we investigated the effect of polymer/conductive-fillerinteractions, as well as the processing and morphological devel-opment of low-percolation-threshold (Φc) conductive-polymer composites. The aim of the study was to produce conductive composites containing less multi-walled CNTs (MWCNTs) than required for pure polypropylene (PP) through two approaches: one using various mix-ing methods and the other using immiscible polymer blends. Variants of the conductive PP composite filledwith MWCNT was prepared by dry mixing, melt mixing, mechanofusion, and compression molding. The percolation threshold (Φc) of the MWCNT-PP composites was most successfully lowered using the mechanofusion process than with any other mixing method (2-5 wt%). The mechanofusion process was found to enhance formation of a perco-lation network structure, and to ensure a more uniform state of dispersion in the CPCs. The immiscible-polymer blends were prepared by melt mixing (internal mixer) poly(vinylidene fluoride) (PVD, PP/PVDF, volume ratio 1:1) filled with MWCN.

Facile In-situ Polymerization of Thermotropic Liquid Crystalline Polymers as Thermally Conductive Matrix Materials

강영권,안예진,김민선,김봉기 한국섬유공학회 2018 Fibers and polymers Vol.19 No.6

Although thermally conductive composites that can efficiently dissipate the heat generated from electronic devices are in high demand, most neat polymers used as matrix materials are problematic because they have poor thermal conductivities. The low thermal conductivity of polymeric materials is caused by structural defects; therefore, it can be improved by increasing the orientational regularity of the polymer chains. Here, main-chain liquid crystalline polymers (LCPs) were designed and synthesized to investigate the effects of liquid crystallinity-induced structural regularity on the thermal conductivity of the polymers. In addition, an in-situ polymerization method was devised for commercial applicability, and the thermal conductivity of the obtained polymer was compared to that of a conventionally polymerized polymer having the same structure. The designed polymers exhibited thermotropic liquid crystalline characteristics, and the polymer with longer spacers between the rigid segments showed relatively higher thermal conductivity exceeding 0.5 W·m-1· K-1 after sample preparation by injection molding. In addition, X-ray diffraction analysis revealed that the differences in the thermal conductivity, depending on the molding temperature during specimen preparation, were caused by variations in chain orientation within the same polymer. Based on the obtained results, it was concluded that LCPs are strong candidate matrix materials for thermally conductive composites; the suggested in-situ polymerization method could be applied practically to the polymerization of polyester-type LCPs.

전도성 고분자와 절연성 고분자의 특성 및 동향

장아영(Ayoung Jang),이지수(Jisu Lee),이상오(Sang Oh Lee),이재웅(Jaewoong Lee) 한국염색가공학회 2023 韓國染色加工學會誌 Vol.35 No.4

Conductive polymers are polymers that conduct electricity like metal conductors. Unlike typical organic polymers, they are polymers that have the electrical, magnetic, and optical properties of metals or semiconductors. For Example, these conductive polymers include Polypyrrole (PPy), Polyaniline (PANI), and Polythiophene (PT). On the other hand, Insulating polymers do not conduct electricity well while providing insulation, which is the opposite of conductivity. With the exception of conductive polymers, most polymers are non-conductors. Insulating polymers include polyimide (PI), polystyrene (PS), and poly(vinyl alcohol) (PVOH, PVA, or PVAl). Although many different polymers exist, we have simply illustrated the properties and recent developments of conductive and insulating polymers, which have opposite properties.

전도성 고분자를 이용한 디스플레이 재료 응용의 최근 연구동향

김정훈 ( Jeong Hun Kim ),김은경 ( Eun Kyoung Kim ) 한국화상학회 2013 한국화상학회지 Vol.19 No.3

전도성 고분자는 고분자가 갖는 높은 투과도와 화학적 구조에 의한 전도성 특성, 좋은 가공성, 낮은 가격과 같은 이점 때문에 전자산업, 특히 디스플레이 재료 개발 분야에서 그 응용에 대한 연구가 활발히 진행되고 있다. 전도성 고분자는 산화환원에 의해 다른 상태의 구조를 갖게 되는데, 이때 색변화, 전도도가 변하게 된다. 따라서 이러한 특징을 이용하여 전도성 고분자의 직접적인 색변화를 이용한 전기변색 디스플레이와 전도성 고분자가 갖는 전기전도도를 이용한 디스플레이 재료들의 연구가 이루어지고 있다. 전도성 고분자는 그 종류마다 다른 전도도를 갖게 되는데, 이는 그 고분자를 이루는 물질에 의해 결정되기 때문이며, 또한 doping level, dopant, 중합방법에 따라 전도도의 조절이 가능한 특징이 있다. 최근 전도성 고분자 응용 분야의 대표적인 선도 연구로는 전기변색 디스플레이, 대전방지, 높은 전도도를 이용한 투명전극 응용 등이 있다. Conductive polymers have been investigated for display material applications due to their high transparency, electrically conductive properties from chemical structures, good processability, and low cost. Conductive polymers have different structure by redox reaction and when they have different structure the color and conductivity can be changed. Therefore, electrochromic display using direct color change and display materials using controllable conductivity have been researched. Conductivity is dependant on species of conductive polymer because conductivity is determined by composition of them and also, conductivity can be controlled by doping level, dopant, polymerization. Recently, these materials are explored in electrochromic display, ESD (Electrostatic Dissipation), transparent electrode with high conductivity and so on.

Factors affecting the electrical conductivity of conducting polymers

Pooja,Kumar Anil,Prasher Parteek,Mudila Harish 한국탄소학회 2023 Carbon Letters Vol.33 No.2

Metals had been significantly substituted by synthetic polymers in most of our daily requirements, thus relaxing our life. Out of many applied areas, synthetic polymers especially conducting polymers had shown their marked effect and potential. Batteries, pseudocapacitors, superconductors, etc. are the potential zones where conducting polymers are chiefly employed owing to their appreciable conductivity, cost efficiency, and corrosion inhibition nature. Apart from energy storage devices, these conducting polymers find their potential application in biosensors, lasers, corrosion inhibitors, electrostatic materials, conducting adhesives, electromagnetic interference shielding, and others. These all applications including energy storage are due to astonishing properties like high conductivity, flexibility, tuneability, easy processibility, chemical, thermal and mechanical stability, easy and enhanced charge transportation, lightweight, etc. Conducting polymers are extensively studied for their application in energy storage batteries, for which the material under investigation needs to be electrically conductive. However, the conducting nature of these specific conducting polymers is dependent on numerous factors. This review discussed the effect of certain potential factors such as polymerization techniques temperature, doping, bandgap, extended conjugation, solvent, etc. on the electrical/electrochemical conductivity of these conducting polymers. These all factors with their specific variations are found to have a noticeable consequence on the electrical conductivity of the investigated conducting polymer and hence on the energy storage carried by them. This review could be proved beneficial to the readers, who can judiciously implement the conclusions to their research related to conducting polymers and their composites for generating highly efficient energy storage systems.

전도성 고분자 물질이 결합된 하이브리드 커플러를 적용한 RF 가스 센서

이용주(Yong-Joo Lee),김병현(Byung-Hyun Kim),이희조(Hee-Jo Lee),홍윤석(Yunseog Hong),이승환(Seung Hwan Lee),최향희(Hyang Hee Choi),육종관(Jong-Gwan Yook) 한국전자파학회 2015 한국전자파학회논문지 Vol.26 No.1

본 논문에서는 2.4 GHz에서 동작하는 90° 하이브리드 커플러 구조에 전도성 고분자 화합물을 적용한 가스 센서를 제안하였다. 가스 센서에서 전도성 고분자 화합물(Conducting Polymer: CP)는 특정 가스를 검출하는 검출 물질로 사용되며, 특정 가스와 반응할 때 대개 물질의 일함수(work function)와 전도도(conductivity) 및 임피던스가 변하게 된다. 이러한 물성변화 특성의 근거로 마이크로파 대역에서 90° 하이브리드 커플러 구조에 전도성 고분자를 적용하여 가변 감쇄기 및 가변 위상 천이기 형태의 센서를 제작하였다. 본 연구에서 제안한 센서는 전도성 고분자 화합물의 높은 전도도를 이용하여 기존 전송선로의 일부를 전도성 고분자 물질로 대체하였다. 실험은 온도 28℃와 상대습도 85 % 환경에서 진행되었으며, 센서에 100 ppm 농도의 에탄올 가스를 노출시켰다. 그 결과, S21의 진폭 특성이 최대 0.13 dB 변하였고, ∠S21 = 360°를 만족하는 주파수가 2.875 MHz 이동한 것을 확인하였다. In this paper, a gas sensor using a modified 90° hybrid coupler structure with conducting polymer which operates at 2.4 GHz is represented. Conducting polymers are used to the gas sensing material in proposed sensors. The conducting polymer varies its electrical property, such as work function and conductivity corresponding to the certain gas. To verify this variation of electrical property of conducting polymer at microwave frequencies, the conducting polymer is incorporated with the 90° hybrid coupler structure, and this proposed sensor operates as reflection type variable attenuator and variable phase shifter. The conducting polymer is employed as impedence-variable transmission lines that cause a impedance mismatching between the general transmission line and conducting polymer. The experiment was conducted with 100 ppm ethanol gas at temperature of 28℃ and relative humidity of 85 %. As a result, the amplitude deviation of S21 is 0.13 dB and the frequency satisfying ∠S21 = 360° is shifted about 2.875 MHz.

다공막 주형에 의한 전도성 고분자 나노와이어의 합성

신화섭,염경호 한국막학회 2012 멤브레인 Vol.22 No.1

양극산화 알루미나(AAO)막의 나노 사이즈 미세공(세공 크기 20 nm, 10 nm 및 200 nm)을 주형으로 사용하여 전도성 고분자인 폴리피롤, 폴리아닐린 중합체 및 폴리피롤/폴리아닐린 공중합체 나노와이어를 제조하였다. 미세공 주형 내에서 전도성 고분자의 성장은 세공의 벽면을 따라 튜브 형태로서 성장하였으며, 3시간 이후에는 내부가 완전히 채워진 나노와이어가 형성되었다. AAO 막을 수산화나트륨 용액으로 퍼리하여 세공 내에 형성된 전도성 고분자 나노와이어를 회수 하였으며. 회수된 나노와이어 직경과 길이는 주형 막의 세공 형상과 일치하였다. 통상의 용액 중합법으로 제조된 전도성 고분자 분말과 비교하여 주형 합성법으로 제조된 전도성 고분자 나노와이어는 결정성과 열적 안정성이 향상되었으며, 전기 저항은 4~60% 감소하였다. We prepared the highly ordered nano-wires of polypyrrole, polyaniline conductive polymers and polypyrrole/ polyaniline conductive copolymers by templating the anodic aluminum oxide (AAO) porous membrane, in which pore diameter was 20 nm, 100 nm and 200 nm. Those conductive polymers were grown from pore inner surface of AAO membrane forming hollow tubes and then wire structures were formed after 3 hour polymerization. By removing AAO membrane templates using sodium hydroxide solution, the conductive polymer nano-wires were successfully obtained, of which diameter and length were close to the ones of nano-pores in AAO membrane template. Crystallinity and thermal stability of the conductive polymer nano-wires were higher than irregular ones that prepared by solution polymerization. Furthermore, the electrical resistance of conductive polymer nano-wires were reduced by about 4~60% compared with that of the irregular polymers prepared by solution polymerization.

Electrochemical properties for ionic liquid/polymer electrolyte systems

Park, Nam Ku,Bae, Young Chan Wiley Subscription Services, Inc., A Wiley Company 2010 Journal of polymer science. Part B, Polymer physic Vol.48 No.2

<P>The ionic liquid (1-ethyl-3-methylimidazolium hexafluorouphophate) ([emim][PF<SUB>6</SUB>]) with different molecular weights of poly(ethylene oxide) (PEO) (MW = 4600; 10,000; 14,000; 20,000; 35,000, and 100,000) has been characterized at various temperatures and compositions using phase behaviors and ionic conductivity. A molecular thermodynamic model based on a combination of the previous theory (BH model) by Chang et al., a nonrandomness theory (NR model), and the Pitzer-Debye-Hückel theory modified by Guggenheim (PDH model) considered not only short-range specific interactions between the polymer and a cation of the ionic liquid (IL), but also long-range electrostatic forces between anions and cations within the IL. We have derived a new melting point depression theory based on this BH-NR-PDH model. We also established an ionic conductivity model, based on the Nernst-Einstein equation, in which the diffusion coefficient is derived from the BH-NR-PDH model. The proposed model takes into account that the mobility of cations in the IL and the motions of the polymer host by expressing the effective chemical potential as the sum of the chemical potentials of the polymer and the IL. To describe the segmental motion of the cation and polymer chain, the effective coordinated unit parameter is introduced. The derived coordinated unit parameter for each state is used to determine the ionic conductivities of the given systems. Quantitative results from the proposed model are in good agreement with experimental data. The results indicate that the molecular weight of the polymer and the surrounding temperature play important roles in determining eutectic points and ionic conductivities of the given systems. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 212–219, 2010</P>