• Title/Summary/Keyword: Cyclic Voltammogram

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A Study on the Stability of Langmuir-Blodgett Films Mixed with Myristic Acid and Stearic Acid (미리스트산과 스테아르산 혼합 LB막의 안정성에 관한 연구)

  • Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.34 no.2
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    • pp.376-381
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    • 2017
  • We were investigated by cyclic voltammetry to the stability through the electrochemical characteristics of Langmuir-Blodgett films mixed with myristic acid and stearic acid. Fatty acid mixture monolayer LB films was deposited by the LB method on the indium tin oxide(ITO) glass. The electrochemical properties was measured by cyclic voltammetry with a three-electrode system in 0.01 N $NaClO_4$ solution. The measuring range is continuously oxidized to 1650 mV, with an initial potential of -1350 mV was reduced. Scanning rates of 50, 100, 150, 200, and 250 mV/s was set. As a result, LB monolayer films of fatty acid mixture was appeared on irreversible processes by the oxidation current from the cyclic voltammogram. Diffusion coefficient (D) of fatty acid mixture was calculated $7.9{\times}10^{-2}cm^2s^{-1}$ at 0.01 N $NaClO_4$ solution.

A Study on the Electrochemical Characteristics of Langmuir-Blodgett Nano-Films of Phospholipid Compound (인지질 화합물의 나노 Langmuir-Blodgett막의 전기화학적 특성에 관한 연구)

  • Jung, A-Jin;Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.29 no.2
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    • pp.311-316
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    • 2012
  • We are investigated to an electrochemical characteristic for Langmuir-Blodgett (LB) films by cyclic voltammetry method. The phospholipid compound was deposited by using the LB method on the Indium tin oxide(ITO) glass. We tried to measure the electrochemical by using cyclic voltammetry with three-electrode system(an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode) in 0.5, 1.0, 1.5 and 2.0 N $NaClO_4$ solution. A measuring range was reduced from initial potential -1350 mV, continuously oxidized to 1650 mV. As a result, LB films of the phospholipid compounds are appeared irreversible process caused by only the oxidation current from the cyclic voltammogram. The diffusivity(D) effect of LB films decreased with increasing of phospholipid compound amount.

A Study on the Stability of Langmuir-Blodgett(LB) Films of Saturated Fatty Acid Monolayer (포화지방산 단분자층 LB막의 안정성에 관한 연구)

  • Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.31 no.3
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    • pp.352-358
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    • 2014
  • We were investigated the stability through the electrochemical characteristics of saturated fatty acid(C12, C14, C16, C18) monolayer LB films by cyclic voltammetry. Saturated fatty acid monolayer LB films was deposited on the indium tin oxide(ITO) glass by the LB method. The electrochemical properties were measured by cyclic voltammetry with a three-electrode system in 0.1 N $NaClO_4$ solution. The measuring range was continuously oxidized to 1650 mV, with an initial potential of -1350 mV was reduced. Scanning rates of 50, 100, 150, 200, and 250 mV/s were set. As a result, LB monolayer films of saturated fatty acid were appeared on irreversible processes by the oxidation current from the cyclic voltammogram. Diffusion coefficient(D) of saturated fatty acid(C12, C14, C16, and C18) was calculated 22.231, 2.461, 7.114 and 2.371 ($cm^2s^{-1}{\times}10^{-4}$) in 0.1 N $NaClO_4$ solution, respectively.

Electrochemical Characteristics of Camphorsulfonic Acid Doped Polyaniline by Secondary Doping (CSA도핑된 폴리아닐린 이차 도핑과 전기화학적 특성)

  • Park Jong-Ho;Cho Seung-Koo
    • Journal of the Korean Electrochemical Society
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    • v.7 no.3
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    • pp.138-142
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    • 2004
  • The polyaniline films of emeraldine base (EB) and leucoemeraldine base (LEB) form doped with cam-phorsulfonic acid (CSA) were prepared by casting the mixed solution of chloroform and m-cresol on ITO (indium tin oxide) electrode. By analyzing UV-vis spectra of the mixed solutions, the effects of the secondary doping by m-cresol were obtained. And the conductivity of polyaniline film was increased with increasing m-cresol content. As the results of analyzing cyclic voltammograms, it was known that the redox peak currents of polyaniline electrode prepared from LEB were larger and more reversible than those of polyaniline eleclrodes prepared from EB. The charge transfer resistances $(R_{ct})$ of polyaniline electrodes were reduced with increasing m-cresol content, showing smaller Rct for LEB/CSA than EB/CSA.

A Electron-Transfer Study on Self-Assembled Viologen Monolayer In different Electrolytes Using Electrochemical Process (전기화학법을 이용한 전해질 변화에 따른 Viologen 자기조립박막의 전하이동 특성 연구)

  • Lee, Dong-Yun;Park, Sang-Hyun;Shin, Hoon-Kyu;Park, Jae-Chul;Chang, Jeong-Soo;Kwon, Young-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07b
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    • pp.878-881
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    • 2004
  • When it converted solar energy or light energy into chemical energy, it studied the electric charge transfer property of the viologen which is used widely as the electron acceptor for the electric charge delivery mediation of the devices. It was formed monolayer in QCM by self-assembled viologen. The absorbed quantities of viologen's electron through peak current and to analyze the electron transfer property of viologen in redox reaction made experiments in cyclic voltammetry among the electrochemical process. It studied the electron transfer relation of viologen from changing the anion in 0.1M NaCl and $NaClO_4$ electrolyte and the interrelation between scan rate and peak current when scan rate increased twice.

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Electrocatalytic Oxidation of NADH at Electrodes of Self-assembled Monolayers Modified with Dopamine (도파민으로 수식된 SAMs 전극에서 NADH의 전기촉매에 의한 산화)

  • Cha, Seong-Keuck
    • Journal of the Korean Chemical Society
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    • v.48 no.2
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    • pp.151-155
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    • 2004
  • The self-assembled mololayers(SAMs)were prepared with cysteine(cys) and subsequently coupled with dopamine(dopa) containing quinone functionality on the gold modified electrodes. The SAMs annealed in ethanol for 6 hours gave a better shaped cyclic voltammogram which had a 0.28 V of formal potential and same redox potential in 0.1M phosphate buffer(pH=7.10). The electrodes were employed to determine concentration of HADH with the result that calibration curve exhibited an excellent correlation(${\geq}$ 0.993) for the concentrations ranging up to 5.0${\times}10^{-4}$ M.

The Potential Barrier Scavenging Effects of the Charged Colloidal Semiconductors at the Magnetized SrO${\cdot}6Fe_{2}O_{3}$ Ceramics Interfaces (자화된 SrO${\cdot}6Fe_{2}O_{3}$ Ceramics 계면에서 대전된 colloid 반도체의 전위장벽 청소효과)

  • Jang Ho Chun
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.29A no.4
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    • pp.22-27
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    • 1992
  • The cyclic voltammogram characteristics at the magnetized SrO${\cdot}6Fe_{2}O_{3}$ ceramics/(($10^{-3}$M KCI + p-Si powders) and /(($10^{-4}$M CsNO$_3$ + n-GaAs powders) suspension interfaces have been studied using the microelectrophoresis and the cyclic voltammetric method. The negatively charged ions are specifically absorbed on the virgin and the magnetized SrO${\cdot}6Fe_{2}O_{3}$ ceramics surfaces. The zeta potentials of the p-Si and n-GaAs colloidal semiconductors are + 41mV and -44.8mV, respectively. The magnetization effects act as potential barriers at the magnetized SrO${\cdot}6Fe_{2}O_{3}$ interfaces. The positivelely charged p-Si and the negatively charged n-GaAs colloidal semiconductors act as potential barriers at the virgin SrO${\cdot}6Fe_{2}O_{3}$ interfaces. On the other hand, the charged p-Si and n-GaAs colloidal semiconductors act as potential barrier scavengers at the magnetized SrO${\cdot}6Fe_{2}O_{3}$ interfaces. The magnetization effects and the charged colloidal semiconductor effects are irreversible and interdependent.

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Growth of Etch Pits on Aluminium Cathode Film (알루미늄 음극박의 에치 피트 성장)

  • Kim, Hong-Il;Kim, Sung-Han;Kim, Young-Sam;Shin, Jin-Sik;Park, Soo-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.338-339
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    • 2005
  • The wider surface of the aluminum foil, electrochemically very important and it is necessary to increase the surface area. A study has been made of the fabrication condition for etching cube texture of high purity aluminium foil and of electrochemical etching of the aluminium foil. In the present work, it is shown there exists a relation between the influence of the pre-treatment time in the NaOH & HCI solution and $H_2SO_4$ concentration in the conversion solution. Also effect of temperature during AC etching was also studied. Result of the etched aluminum film is shown in the typical SEM images. Its electrochemical characteristics were investigated by cyclic voltammetry. And effects of current density and frequency is also reported. Cyclic voltammogram showed that the protective oxide film was formedon the inner surfaces of etch pit. the frequency influence resistance of oxide film in AC etching.

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Electrochemical Reduction of Methylene Blue and the Effect of Surfactants and Poly-Electrolytes (Methylene Blue의 전기화학적 환원과 계면활성제 및 고분자 전해질의 영향)

  • Kim, Il-Kwang;Jeong, Seung-Il;Chun, Hyun-Ja
    • Journal of the Korean Chemical Society
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    • v.39 no.1
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    • pp.57-65
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    • 1995
  • The electrochemical reduction of methylene blue (MB) in 1.0${\times}$10-2 M KNO3 aqueous solution was investigated by direct current (DC), differential pulse (DP) polarography, cyclic voltammetry (CV) and controlled potential coulometry (CPC). The electrode reduction of melthylene blue was processed CE reaction mechanism by two electrons transfer at the first reversible wave (- 0.18 volts vs. Ag/AgCl). MB was strongly adsorbed on the stationary mercury electrode and the reduction product of conptrolled potential electrolysis was rapidly auto-oxidized in air to the original methylene blue. Upon the basis of interpretation of cyclic voltammogram with pH change, possible CE electrode reaction mechanism was suggested.

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Effect of pH on the Iron Autoxidation Induced DNA Cleavage

  • Kim, Jong-Moon;Oh, Byul-Nim;Kim, Jin-Heung;Kim, Seog-K.
    • Bulletin of the Korean Chemical Society
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    • v.33 no.4
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    • pp.1290-1296
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    • 2012
  • Fenton reaction and iron autoxidation have been debated for the major process in ROS mediated DNA cleavage. We compared both processes on iron oxidation, DNA cleavage, and cyclic voltammetric experiment at different pHs. Both oxidation reactions were preferred at basic pH condition, unlike DNA cleavage. This indicates that iron oxidation and the following steps probably occur separately. The ROS generated from autoxidation seems to be superoxide radical since sod exerted the best inhibition on DNA cleavage when $H_2O_2$ was absent. In comparison of cyclic voltammograms of $Fe^{2+}$ in NaCl solution and phosphate buffer, DNA addition to phosphate buffer induced significant change in the redox cycle of iron, indicating that iron may bind DNA as a complex with phosphate. Different pulse voltammogram in the presence of ctDNA suggest that iron ions are recyclable at acidic pH, whereas they may form an electrically stable complex with DNA at high pH condition.