Effect of Oxidant/Monomer Ratio on Conductivity of Ferric Chloride Oxidized Polypyrrole

2010 ◽  
Vol 663-665 ◽  
pp. 666-669
Author(s):  
Yuan Ming Huang ◽  
Bao Gai Zhai ◽  
Qing Lan Ma ◽  
Xiao Yan Kong

A series of polypyrrole samples were synthesized by oxidizing pyrrole in the aqueous medium of ferric chloride, and the relation between oxidant/monomer ratio and the electrical conductivity of polypyrrole was studied by increasing the ratio from 0.25:1 to 2.5:1. Our results showed that the conductivity of polypyrrole was dependent on the mole ratio of the oxidant to pyrrole, and a maximum value for electrical conductivity of 1500 S/m was achieved for a ratio of 0.75:1.

2010 ◽  
Vol 663-665 ◽  
pp. 682-685
Author(s):  
Yuan Ming Huang ◽  
Fu Fang Zhou ◽  
Qing Lan Ma ◽  
Ming Meng ◽  
Chun Xu Pan

The effects of dopant 5-sulfosalicylic acid on the conductivity of polypyrrole were investigated. Under the condition of fixed molar ratio of oxidant-to-monomer (0.75: 1.00), a dozen of polypyrrole samples were made from chemical polymerizing the monomer pyrrole in aqueous medium by varying the dopant-to-monomer molar ratio. It was found that the dopant affected the conductivity and particle size of the synthesized polypyrrole. A maximum value for electrical conductivity of 5575 S/m was achieved when the molar ratio of dopant: oxidant: monomer is 2.25:0.75:1.00.


2006 ◽  
Vol 514-516 ◽  
pp. 43-47 ◽  
Author(s):  
Gonçalo Gonçalves ◽  
Elvira Fortunato ◽  
J.I. Martins ◽  
Rodrigo Martins

In this work, the relation between oxidant/monomer ratio and the electrical conductivity of polypyrrole was studied using different ratios. We achieved a maximum value for electrical conductivity of 7.5 S/cm for a ratio of 2:1. We also developed a chemical dip-coating process to produce the cathode layer in tantalum capacitors. We obtained capacitances of about 80 µF after 8 cycles using the sequence Monomer/Oxidant.


2010 ◽  
Vol 663-665 ◽  
pp. 674-677
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai ◽  
Fu Fang Zhou ◽  
Chun Xu Pan

The effects of dopant 5-sulfosalicylic acid on the conductivity of polypyrrole were investigated. Being nonhygroscopic, ammonium persulfate was used as the oxidant. Under the condition of fixed molar ratio of oxidant-to-monomer (0.375:1.00), a dozen of polypyrrole samples were made from chemical polymerizing the monomer pyrrole in aqueous medium by varying the dopant-to-monomer molar ratio. It was found that the dopant affected the conductivity and particle size of the synthesized polypyrrole. A maximum value for electrical conductivity of 5575 S/m was achieved when the molar ratio of dopant: oxidant: monomer is 2.25:0.375:1.00.


2021 ◽  
Vol 73 (1) ◽  
pp. 160-168
Author(s):  
T.K. Jumadilov ◽  
◽  
B. Totkhuskyzy ◽  
L.K. Yskak ◽  
T. Askar ◽  
...  

The remote interaction between a weak polyacrylic acid polyelectrolyte (gpac) and a weak polyethyleneimine polybase (gpei) is studied as a function of time at their different molar ratios and states in an aqueous medium. To predict the possibility of activation of the studied hydrogels, electrochemical properties were studied by conductometry and pH metry. During pH measurement, it was found that 24 hours of pH have the lowest values, indicating a high content of H+ ions in the aqueous medium. The dependence of the specific electrical conductivity, the maximum value at the ratio of 3:3 (PAC:PEI) and it coincides with the result of pH from the ratio of components. The obtained results indicate that significant changes in the electrochemical and conformational values of the initial macromolecules in the interpolymer system occur in this interpolymer system. Thus, studies have shown on the presence of a remote interaction between hydrogels and their mutual activation. With an increase in the content of one of the hydrogels in the solution, a significant increase in the swelling of hydrogels is observed in proportion to the concentration of the second component, which indicates their mutual activation.


1996 ◽  
Vol 424 ◽  
Author(s):  
Hong-Seok Choi ◽  
Jae-Hong Jun ◽  
Keun-Ho Jang ◽  
Min-Koo Han

AbstractThe material properties of laser-annealed a-Si:Nx films were investigated. The a-Si:Nx films for laser-annealing were deposited by rf plasma enhanced chemical vapor deposition (PECVD) with NH3 and SiH4 gas mixtures. At the 0.35 of NH3/SiH4 ratio, the optical band-gap was abruptly increased to 2.82 eV from 2.05 eV by laser-annealing which indicates that Si-N bonding comes to be notable at that ratio. The electrical conductivity showed the maximum value of 4× 10-6 S/cm at the 0.11 of NH3/SiH4 ratio where the grain growth and the increase of Si-N bonding are optimized for the enhancement of electrical conductivity. The σP/σD ratio which is related to the defects states for photo generation centers was decreased with increasing NH 3/SiH 4 ratio. Our experimental data showed that the optical band gap and electrical conductivity of laserannealed a-Si:Nx films were dominantly affected by the NH3/SiH4 ratio at the 250 mJ/cm2 of laser-annealing energy density.


2021 ◽  
Vol 63 (9) ◽  
pp. 1376
Author(s):  
Н.И. Сорокин ◽  
В.В. Гребенев ◽  
Д.Н. Каримов

The anisotropy of anionic conductivity in crystals of a superionic conductor CeF3 with the tysonite structure (sp. gr. P-3с1) has been studied for the first time. The conductivity measurements at temperatures from 300 K to 600 K were carried out along the principal a- and c-axes of trigonal unit cell of the crystal. The maximum value of electrical conductivity is observed along the c-axis. The superionic CeF3 crystals have the weak anisotropy of electrical conductivity equal to σ||c/σ||a = 2.4 and σ||c = 5.6 10–4 S/cm at 500 K. The anisotropy effect of anionic conductivity in individual fluorides with the tysonite structure is discussed in connection with the peculiarities of their atomic structure.


2019 ◽  
Vol 14 (30) ◽  
pp. 64-72
Author(s):  
Ahmad A. Hasan

A.C electrical conductivity and dielectric properties for poly(vinyl alcohol) (PVA) /poly (ethylene oxide) (PEO) blends undopedand doped with multi-walled carbon nanotube (MWCNTs) withdifferent concentrations (1, and 3 wt %) in the frequency range(25x103 - 5x106 Hz) were investigated. Samples of (PVA/PEO)blends undoped and doped with MWCNTs were prepared usingcasting technique. The electrical conductivity measurements showedthat σA.C is frequency dependent and obey the relation σA.C =Aωs forundoped and doped blends with 1% MWCNTs, while it is frequencyindependent with increases of MWCNTs content to 3%. Theexponent s showed proceeding increase with the increase of PEOratio (≥50%) for undoped blends samples, while s value for dopedblends exhibits to change in different manner, i.e. s increases andreach maximum value at 50/50 PVA/PEO, then decreases forresidual doped blends samples with 1% MWCNTs on the other handthe exponent s decrease and reach minimum value at 50/50PVA/PEO for samples doped with 3% MWCNTs, then return toincrease. The results explained in different terms.


Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 410
Author(s):  
Youfeng Lai ◽  
Lixue Xia ◽  
Qingfang Xu ◽  
Qizhong Li ◽  
Kai Liu ◽  
...  

Doping of nitrogen is a promising approach to improve the electrical conductivity of 3C-SiC and allow its application in various fields. N-doped, <110>-oriented 3C-SiC bulks with different doping concentrations were prepared via halide laser chemical vapour deposition (HLCVD) using tetrachlorosilane (SiCl4) and methane (CH4) as precursors, along with nitrogen (N2) as a dopant. We investigated the effect of the volume fraction of nitrogen (ϕN2) on the preferred orientation, microstructure, electrical conductivity (σ), deposition rate (Rdep), and optical transmittance. The preference of 3C-SiC for the <110> orientation increased with increasing ϕN2. The σ value of the N-doped 3C-SiC bulk substrates first increased and then decreased with increasing ϕN2, reaching a maximum value of 7.4 × 102 S/m at ϕN2 = 20%. Rdep showed its highest value (3000 μm/h) for the undoped sample and decreased with increasing ϕN2, reaching 1437 μm/h at ϕN2 = 30%. The transmittance of the N-doped 3C-SiC bulks decreased with ϕN2 and showed a declining trend at wavelengths longer than 1000 nm. Compared with the previously prepared <111>-oriented N-doped 3C-SiC, the high-speed preparation of <110>-oriented N-doped 3C-SiC bulks further broadens its application field.


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