scholarly journals CHANGE IN THE SURFACE STRUCTURE OF SEMICONDUCTOR POLYMER FILMS DURING REVERSE OXIDATION-REDUCTION

Author(s):  
Анатолий Анатольевич Крылов ◽  
Александра Ивановна Иванова ◽  
Владимир Георгиевич Алексеев ◽  
Мариана Александровна Феофанова ◽  
Надежда Владимировна Баранова

Методом растровой электронной микроскопии исследована морфология поверхности пленок полупроводниковых полимеров: полианилина, поли-о-толуидина, поли- α -нафтиламина. Пленки получены электрохимическим синтезом из подкисленных минеральными кислотами растворов их мономеров методом циклической вольтамперометрии. Пленки сформированы на платиновых подложках, сделанных по принципу биметаллических пластинок. Процессы обратимого окисления и восстановления полученных пленок осуществляли с применением электрического тока в водных растворах соляной кислоты, что приводило к допированию полимеров хлорид анионами. Показано, что поверхность пленок полианилина и поли-о-толуидина имеет схожую структуру, состоящую из многочисленных сферических зерен размером от 1 до 5 мкм. Поверхность пленок поли- α -нафтиламина существенно отличается и состоит из дендронов и крупных пор. При этом, во всех случаях наблюдаемые надмолекулярные образования для пленок в окисленном состоянии имеют несколько больший размер, чем для пленок в восстановленном состоянии, что обусловлено изменением конформации макромолекул. The surface morphology of films of semiconducting polymers: polyaniline, poly-o-toluidine, poly-α-naphthylamine was studied by scanning electron microscopy. The films were obtained by electrochemical synthesis from solutions of their monomers acidified with mineral acids by the method of cyclic voltammetry. The films are formed on platinum substrates made according to the principle of bimetallic plates. The processes of reversible oxidation and reduction of the obtained films were carried out using an electric current in aqueous solutions of hydrochloric acid, which led to the doping of polymers with chloride anions. It was shown that the surface of films of polyaniline and poly-o-toluidine has a similar structure, consisting of numerous spherical grains ranging in size from 1 to 5 pm. The surface of poly-α-naphthylamine films is significantly different and consists of dendrons and large pores. In this case, in all cases, the observed supramolecular formations for films in the oxidized state are somewhat larger than for films in the reduced state, which is due to a change in the conformation of macromolecules.

2017 ◽  
Vol 70 (9) ◽  
pp. 1025 ◽  
Author(s):  
Max E. Easton ◽  
Lisa C. Player ◽  
Anthony F. Masters ◽  
Thomas Maschmeyer

The reversible electrodeposition of zinc was investigated in an aqueous electrolyte containing zinc bromide (50 mM) and 1-ethylpyridinium bromide ([C2Py]Br, 50 mM) by cyclic voltammetry, chronoamperometry, and scanning electron microscopy. Unusual voltammetric behaviour for the Zn/ZnII redox couple was observed in the presence of [C2Py]Br. Passivation of the redox couple was observed after a single deposition–stripping cycle at switching potentials more negative than −1.25 V versus Ag/AgCl. This unusual behaviour was attributed to the reduction of 1-ethylpyridinium cations to pyridyl radicals and their follow-up reactions, which influenced the zinc electrochemistry. This behaviour was further seen to modify the nucleation process of electrodeposition, which altered the morphology of zinc electrodeposits.


2005 ◽  
Vol 04 (02) ◽  
pp. 245-252 ◽  
Author(s):  
JING-RU WU ◽  
EDWIN JAHNGEN ◽  
KUANG-PANG LI ◽  
WAN-SUN TSE ◽  
PING CHIANG ◽  
...  

Vertically oriented multiple-walled carbon nanotubes (MWCNTs) aligned on a silicon substrate were covalently bonded with horseradish peroxidase (HRP) and used as biosensors or electrodes. The modified platform was investigated with Scanning Electron Microscopy (SEM), UV-Vis spectrophotometer and Cyclic Voltammetry (CV). The enzyme catalyzed reaction and the subsequent reduction of the enzymatic products by the platform were carefully investigated. The assay was done by measuring the absorbance of the dye formed from the reaction product of the substrates (phenol) and 4-aminoantipyrine. From the linear response, phenol can be quantitized in the range from 47 ppm to 750 ppm with a detection limit of 19 ppm (based on S/N = 3). The resulting modified aligned MWCNTs still exhibited enzymatic activities after storage of 13 days. The activity of the attached HRP was also demonstrated electrochemically.


2010 ◽  
Vol 64 (1) ◽  
Author(s):  
Altuğ Kümbül ◽  
Ersen Turaç ◽  
Tuğba Dursun ◽  
Ertuğrul Şahmetlioğlu

AbstractElectrochemical copolymerization of N 1,N 3-bis(thiophene-3-ylmethylene)benzene-1,3-diamine (TMBA) with 3,4-ethylenedioxythiophene (EDOT) was carried out in a CH3CN/LiClO4 (0.1 M) solvent-electrolyte via potentiodynamic electrolysis. Chemical structure of the monomer was determined by nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FTIR) spectroscopy. The resulting copolymer was characterized by cyclic voltammetry (CV), FTIR, scanning electron microscopy (SEM), and thermogravimetry analyses (TGA). Conductivity measurements of the copolymer and PEDOT (poly(3,4-ethylenedioxythiophene)) were carried out by the four-probe technique.


2014 ◽  
Vol 92 (12) ◽  
pp. 1139-1144 ◽  
Author(s):  
Tao-Tao Pang ◽  
Li-Ming Du ◽  
Hai-Long Liu ◽  
Yun-Long Fu

Numerous techniques have focused on the ability of p-sulfonated calix[n]arene to form complexes with tryptophan. Scanning electron microscopy and Fourier transform infrared spectroscopy were utilized to study the organization and molecular structure of different layers of the electrode surface. Scanning electron microscopy results showed that SC4A displayed a cubic structure whereas SC6A and SC8A displayed dendrite structures. The electrochemical properties and potential complex formation between SCnA and tryptophan were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Cyclic voltammetry experiments showed that the gold electrode was successfully functionalized by self-assembled cysteamine and SC4A. Electrochemical impedance spectroscopy results showed the observation of the tryptophan–SCnA interaction and indicated that SC4A had the highest sensitivity to tryptophan and allowed 2.04 μg L−1 tryptophan to be detected. Electrochemical impedance spectroscopy analysis and molecular modeling calculation confirmed that SC4A has higher tryptophan sensitivity than SC6A and SC8A.


2012 ◽  
Vol 512-515 ◽  
pp. 944-947 ◽  
Author(s):  
Jia Wei Deng ◽  
Huan Pang ◽  
Shao Mei Wang ◽  
Jiang Shan Zhang

Graphene oxide nanoplate-MnO2composites have been synthesized by oxidizing part of the carbon atoms in the framework of graphene oxide nanoplates at ambient temperature. The composites were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV). Their microstructures and morphologies have affected their electrochemical properties. Compared with MnO2nanoparticles, the nanocomposite prepared reveals better electrochemical properties as a supercapacitor electrode material.


Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 977
Author(s):  
Min Hee Joo ◽  
So Jeong Park ◽  
Hye Ji Jang ◽  
Sung-Min Hong ◽  
Choong Kyun Rhee ◽  
...  

Terpyridine-functionalized Ti nanospike electrodes (TiNS-SiTpy) were developed and applied to cyclic voltammetry and amperometry of Ln (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb) ions and mixed Eu (III) + Ln (III) ions in a 0.1 M NaClO4 electrolyte. Electrodeposition was successfully performed over TiNS-SiTpy electrodes, which were fully examined by scanning electron microscopy, X-ray diffraction crystallography, Fourier-transform infrared spectroscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, photoluminescence (PL), and PL decay kinetics. The Gd and Tb ions were found to increase PL intensities with 10× longer lifetimes of 1.32 μs and 1.03 μs, respectively, compared with that of the electrodeposited Eu sample. The crystal phase and the oxidation states were fully examined for the mixed Ln (Eu + Gd and Eu + Tb) complex structures.


2018 ◽  
Vol 15 (1) ◽  
pp. 62
Author(s):  
Pandi Kurniawan ◽  
Erman Taer ◽  
Usman Malik ◽  
Rika Taslim

Activated carbon electrode have been prepare from durian shell focused in KOH concentration variations at chemical activation process. The preparation of carbon electrodes begins with pre-carbonization process, grinding using Hard Grinder and ball milling, after that followed by sieving process with particle size at range of 39 - 52 μm. Chemical activation was performed by using KOH activator agent with concentration variation of 0.5 M, 0.6 M, 0.7 M. Carbon powder are formed to pellet form using Hydraulic Press at a 8 ton compression pressure. The carbonization process is carried out a temperature of 600°C in the N2 gas atmosphere at a temperature of 900°C for 2 hours. The electrodes characterization are performed to determine the physical and electrochemical properties.The physical properties such as density, degree of cristanility, surface morfology was analyzed by calculate the electrode dimension such as, mass, thickness and diameter, X-ray diffraction analysis and Scanning Electron Microscopy Analysis. the electrochemical properties was studied the cell capacitance and the electrode capacitance specific using Cyclic Voltammetry method. the electrode density were decrease with the increasing the KOH concentration. The smallest density has been found at electrode using a KOH concentration of 0.7 M. The XRD test showed a carbon was amorfphuse structure identified by existing two broadening peaks at an angle of 2θ, ie 24.967°, 44.315° and 81.332° which describes the  (002), (100) and (112) planes. Furthermore, samples were analyzed by Scanning Electron Microscopy and X-ray diffraction. The  cyclic voltammetry result, obtained the highest specific capacitance of 89.05 F/g and cell capacitance 24,04 F was found at electrode with a KOH  concentration of 0.7 M. From this research it can be concluded that the KOH optimum concentration was 0.7 M.


2011 ◽  
Vol 694 ◽  
pp. 838-841
Author(s):  
Xue Mei Cui ◽  
Gui Fu Ding ◽  
Yan Wang ◽  
Wen Jing Lu ◽  
Hui Shen

We propose a novel preparation technology of CNTs modified electrode. CNTs are mixed with polymer into homogenate by mechanical ball grinder; spin homogenate into composite film; solidify and polish composite film; chemical etch polymer partly from the surface of the composite film, in order to keep part of the CNTs be inserted in polyimide and the remainder outside of film, then CNTs modified electrode can be got. The morphologies of CNTs modified electrode are observed by field emission scanning electron microscopy (FESEM). The application of CNTs modified electrode in alum solution battery is demonstrated. Cyclic voltammetry of CNTs modified electrodes in V4+ solution is discussed.


2016 ◽  
Vol 19 (3) ◽  
pp. 145-150 ◽  
Author(s):  
Meysam Karimi ◽  
Mohammad Rabiee ◽  
Mojgan Abdolrahim ◽  
Mohammadreza Tahriri ◽  
Daryoosh Vashayee ◽  
...  

We present a study of the effect of graphene–PANI nanocomposites on the sensitivity of the urea and glucose multisensory. We used an electroctrochemical multisensor based on two electrodes located in a reservoir with two separate channels. The urease and glu-cose oxidase (GOD) were employed for detecting the urea and glucose, respectively. We characterized the graphene and graphene-PANI samples with X-ray Diffraction (XRD) analysis and scanning electron microscopy (SEM) observations. We further performed the Cyclic voltammetry and Amperometry tests. The collected experimental results revealed that the intensity of the peak significantly increases with the concentration of the urea and glucose.


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