• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.197.2-197.2
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• 2014

그래핀(graphene)의 라만 스펙트럼은 전하밀도(charge density)와 기계적 변형(strain)에 민감하여 연구에 널리 활용되고 있다. 본 연구에서는 기계적 박리법으로 만든 그래핀에 황산 수용액으로 p-형 화학도핑(chemical doping)을 유발시키고 전하밀도의 변이에 따른 라만 스펙트럼의 변화를 조사하였다. 이러한 변화를 통해 황산과 물 분자의 계면 확산을 이해하고, $SiO_2/Si$ 기판의 화학적 특성이 미치는 영향을 파악하고자 하였다. 분자의 효율적인 계면 확산을 위해 고온 산화반응을 이용하여 그래핀의 기저면에 나노공(nanopore)을 만든 후, 액상에서 라만 스펙트럼을 측정하였다. 증류수 속에 담궜을 때 물 분자가 그래핀-기판 계면 사이로 확산되면서 열처리에 의해 유발된 정공이 사라짐을 확인하고, D-봉우리의 가역적인 변화로부터 그래핀의 구조적 변화를 유추하였다. 황산 농도를 증가시켰을 때 G와 2D-봉우리의 진동수가 상호간에 일정한 비율로 증가하여 정공의 밀도가 증가함 알 수 있었다. 동일한 시료에 대해 황산의 농도를 감소시킴으로써 p-형 도핑을 제거하고 동일한 반응을 가역적으로 반복할 수 있었다. 상기한 분자의 2차원 확산 현상은 나노공의 유무와 기판의 전처리 조건에 따라 크게 달라진다는 사실을 확인 할 수 있었다. 또한 여러 파장에서 측정된 전하밀도와 기계적 변형에 의한 G와 2D-봉우리의 진동수 변화로부터 다른 연구자들이 활용할 수 있는 검정곡선을 제시하였다.

• Journal of the Korean Chemical Society
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• v.57 no.5
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• pp.625-633
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• 2013

A type of polycyclotriphosphazene derivative (PCTPD), hexasulfanilic acid polycyclotriphosphazene (HSACP) and HSACP grafting SPEEK, sulfonated poly[2-(petachloropolycyclotriphosphazene-oxy)] etheretherketone (SPPSACPEEK) were synthesized, which were characterized by FTIR and $^{31}P$ NMR. Then three types of composite membranes such as HSACP grafting SPEEK, HSACP blending SPEEK, and nano $Y_2O_3$ doping and HSACP grafting SPEEK, respectively, were continuously prepared by solution-casting method. Comparing to SPEEK membranes with different amount of HSACP grafted or blended, grafting 15 wt% HSACP and doping 10 wt% nano $Y_2O_3$ SPEEK membrane conducted outstanding overall behavior of proton conductivity reaching $3.18 {\times}10^{-2}$ S/cm at $90^{\circ}C$ which was merely junior to SPEEK with 15 wt% HSACP grafted, methanol permeability coefficient getting $9.46{\times}10^{-8}cm^2{\cdot}s^{-1}$, swelling degree of 20.9% and solid residue of 98.98% which was superior to all specimen.

• Advances in materials Research
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• v.3 no.2
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• pp.117-128
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• 2014

Processable conducting polyaniline derivative with free amine functional groups was successfully synthesized from the monomer o-phenylenediamine in aqueous hydrochloric acid medium using ammonium persulfate as an oxidative initiator. The synthesized poly(o-phenylenediamine) (PoPD) in critical condition was found to be completely soluble in common organic solvents like dimethyl sulfoxide, N,N-dimethyl formamide etc. From the intrinsic viscosity measurement, the optimum condition for the polymerization was established. The polymer was characterized by ultraviolet visible spectroscopy, Fourier transform infrared spectroscopy, proton magnetic resonance spectroscopy ($^1HNMR$) and thermogravimetric (TGA) analyses. The weight average molecular weights of the synthesized polymers were determined by the dynamic light scattering (DLS) method. From the spectroscopic analysis the structure was found to resemble that of polyaniline derivative with free amine functional groups attached to ortho/meta position in the phenyl ring. However, very little ladder unit was also present with in the polymer chain. The moderate thermal stability of the synthesized polymer could be found from the TGA analysis. The average DC conductivity of $2.8{\times}10^{-4}S/cm$ was observed for the synthesized polymer pellet after doping with hydrochloric acid.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.4
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• pp.439-445
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• 2007

Proton exchange membrane Fuel Cells(PEMFCs) have been spotlighted because of their broad potential application for potable electrical devices, automobiles and residential usages. However, their utilization is limited to low temperature operation due to the electrolyte dehydration at high temperature. High temperature PEMFC operation offers high CO tolerance and easy water management. This review presents development of high temperature($120{\sim}200^{\circ}C$) PEMFC. Especially, PEMFC which is based on acid-doped PBI membrane is discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.3
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• pp.215-222
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• 2001

Polyaniline-Camphorsulfonic Acid Emeraldine Salt(PANI-CSA ES) was prepared by doping Polyaniline Ermeralidine Base(PANI EB) with DL-10-Camphorsulfonic Acid(CSA). PANI-CSA ES was solved in an organic solvent by ultrasonification for different periods of time and its surface resistivity was measured. Several PANI-CSA ES solutions solved in different organic solvents were prepared and their surface resistivities were measured. Thermal stability of film casted with PANI-CAS ES solution in m-cresol was estimated by measuring its surface conductivity and the content of this moisture and organic solvents. PANI-CSA ES was blended with different polymeric binders to improve its physical properties and the surface resistivities of several kinds of PANI-CSA ES blends were measured as a function of the content of PANI-CSA ES. PANI-CSA ES polymerized by 1-step oxidative polymerization was prepared and its surface resistivity was measured.

• 한국초전도학회:학술대회논문집
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• 2009.07a
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• pp.39-39
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• 2009

• Analytical Science and Technology
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• v.8 no.4
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• pp.631-636
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• 1995

Electrochemical properties of self-dopable poly(aniline N-butylsulfonate)s in various acidic medium were investigated by spectroelectrochemical techniques. Cyclic voltammetric study showed more than two reversible process of one electron transfer, the potential and peak intensity of which were dependent on the acid concentration and dopant ion. Spectroscopic study at different oxidation level indicated that the electrochromic switching of the poly(aniline N-alkylsulfonate)s film involves structural changes from benzenoid ring to quinoid ring. Spectrocyclic voltammetry together with impedance spectra of the PANBUS film in 0.1 M $LiClO_4$ solution of acetonitrile containing 0.46 M of perchloric acid showed two types of highly conductive states at the intermediate oxidation levels, which can be related to the metallic polaron states doped by two different process.

• Electrical & Electronic Materials
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• v.10 no.7
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• pp.713-718
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• 1997

Polyaniline free standing films cast from N-methyl-2-pyrrolidinone(NMP) solution, camphorsulfonic acid(HCSA), dodecylbenzensulfonic acid(HDBSA), inorganic matter(carbon black, graphite) and metal(silver) were prepared by processings. The properties of these films such as crystallinity, near-infrared absorption spectra and conductivity were investigated. The HCSA and HDBSA doped polyaniline films cast from m-cresol and chloroform solvents showed the metallic property and high crystallinity, respectively. The value of conductivity in the HCSA doped polyaniline film obtained 180 S/cm. We have obtained the value of conductivity 200 S/cm in the metal(silver) doped polyaniline film, which is higher than that of the HCSA doped polyaniline film. The metal(silver) doped polyaniline film shows good properties as a electromagnetic shielding material.

• Journal of Sensor Science and Technology
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• v.10 no.2
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• pp.125-133
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• 2001

Conducting polymer sensors show high sensitivity when exposed to volatile organic compounds gases at room temperature. The 8 sensor array using by polypyrrole and polyaniline has been fabricated by chemical polymerization for measuring sensing characteristics of VOCs gases. Conducting polymer was polymerized by using distilled pyrrole, aniline as a monomer and ammonium persulfate (APS) as an oxidant and dodecylbenzene sulfonic acid (DBSA) as a dopant. Dedoped film was synthesized by reverse voltage and redoped film was synthesized by using 1-octanesulfonic acid sodium salt as another dopant in electrochemical cell. The sensitivity and reversibility were influenced by doping, dedoping, redoping and thickness for the polypyrrole and polyaniline. We investigated the relation between the structure of conducting polymer and sensitivity of these sensors through the analysis of scanning electron microscope (SEM), scanning probe microscope (SPM) and $\alpha$-step.

• The Korean Journal of Food And Nutrition
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• v.21 no.1
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• pp.35-42
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• 2008

To develop physiological functionality of Omija extracted with water was evaluated on antioxidative activity. Omija, high acid material with pH 3.6, contain $57.5{\pm}1.03%$ of moisture, and $18.8{\pm}0.12%$ of crude fat. This material have $12.6{\pm}0.04%$ of carbohydrate and $11.1{\pm}0.07%$ of crude protein as well, but ash and crude protein contents were found less than 10%. 10 mineral contents were also found, too; K and Ca showed the highest level, then Al, Mg, Na and Mn were followed. In composition amino acid contents, glutamic acid took the largest portion, $131.7{\pm}1.3$ mg/100 g, aspartic acid $51.5{\pm}0.6%$, and other composition amino acid under 50%. In case of free sugar contents, 7 types were found. Most of them were glucose and fructose. Total phenolic compounds showed the highest level, $2,862.6{\pm}31.7$ mg/100 g. $197.8{\pm}14.6$ mg/100 g of flavonoid and $225.6{\pm}18.2$ mg/100 g were included. In terms of electron donating ability, radical scavenging ability activated as the amount of Omija extract increased. In particular, Omija extract in 1,000 ${\mu}g/m{\ell}$ demonstrated almost similar electron donating ability, $72.4{\pm}0.21%$, to BHT. It was also found that antioxidant activities of electron donating ability, SOD-like ability, hydroxyl radical scavenging ability and nitrite scavenging ability were highly promoted as Omija extract concentration increased. The nitrite scavenging ability was significant when the extract belonged to strong acid region and doping concentrations increased.