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P. Savitha D. N. Sathyanarayana 《Journal of polymer science. Part A, Polymer chemistry》2005,43(14):3040-3048
Two series of terpolymers, one of o‐/m‐toluidine and aniline with o‐aminobenzoic acid and the other of o‐/m‐toluidine and aniline with m‐aminobenzenesulfonic acid, have been synthesized by oxidative polymerization via an emulsion method with ammonium persulfate as the oxidant and HCl as the external dopant. The terpolymers exhibit excellent solubility and retain the high conductivity (∼1 S cm−1) characteristic of the unsubstituted homopolymer, polyaniline. The terpolymers also possess higher thermal stability than polyaniline. This can be attributed to the presence of internal doping groups and substituents, which introduce flexibility to the otherwise rigid polyaniline backbone. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3040–3048, 2005 相似文献
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Janakiraman Vivekanandan Arunachalam Mahudeswaran Xiao-Yan Tang Sangamesh G. Kumbar Pachanoor Subbaian Vijayanand 《Chemical Papers》2015,69(7):964-972
Novel copolymers of poly(aniline-co-m-chloroaniline)-doped dodecylbenzenesulphonic acid (DBSA) with embedded silver nanoparticles were synthesised using the in situ chemical oxidative method. The structural properties of the copolymers were characterised using the UV-VIS and FTIR spectroscopic methods. The crystalline nature of the copolymer was demonstrated by way of the X-ray diffraction (XRD) pattern. Scanning electron microscopy (SEM) revealed the presence of particle agglomerates measuring 50 nm to 100 nm on the surface of the nanocomposites. The electrical conductivity of the copolymer was dependent on the monomer composition and was found to be in the range of 10?2 S cm?1 to 10?6 S cm?1 with an increasing chloroaniline content and exhibiting improved solubility. 相似文献
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James R. Durig Savitha S. Panikar Keith A. GlennYa Ying Zheng Gamil A. Guirgis 《Vibrational Spectroscopy》2011,55(2):250-257
Infrared and Raman spectra (3500-60 cm−1) of gas and/or liquid and solid 1-chloro-1-silacyclopentane (c-C4H8SiClH) have been recorded and the vibrational data indicate the presence of a single conformer with no symmetry which is consistent with the twisted form. Ab initio calculations with a variety of basis sets up to MP2(full)/aug-cc-pVTZ predict the envelope-axial and envelope-equatorial conformers are saddle points with nearly the same energies but much lower in energy than the planar conformer. Density functional theory calculations by the B3LYP method predicts slightly lower energies for the two envelope forms and considerably lower for the planar form. By utilizing the MP2(full)/6-31G(d) calculations the force constants, frequencies, infrared intensities, band contours, Raman activities, and depolarization values have been obtained to support the vibrational assignment. Estimated r0 structural parameters have been obtained from adjusted MP2(full)/6-311 + G(d, p) calculations. These experimental and theoretical results are compared to the corresponding quantities of some other five-membered rings. 相似文献
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T. Savitha S. Selvasekarapandian C. S. Ramya 《Journal of Solid State Electrochemistry》2008,12(7-8):857-860
In the present study, Li x AlZr[PO4]3 (x = 1.8, 2.0, 2.2) has been prepared by the Pechini-type polymerizable precursor method, and structural and electrical analyses have been performed. Formation of the compound has been confirmed from X-ray diffraction pattern. Vibrational analysis has been performed using Fourier transform infrared spectroscopy. Ion transport mechanism has been analyzed using the AC impedance technique. Electrical characterization reveals that the maximum conductivity (4.4 × 10?5S cm?1) has been observed for the sample Li2.2AlZr[PO4]3 at 673K. 相似文献
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G. Savitha 《Tetrahedron letters》2008,49(51):7260-7263
Spiro dihydrofuran fluorene derivatives were prepared via [3+2] oxidative cycloaddition of 1,3-dicarbonyl compounds to 9-benzylidene-9H-fluorene and 2-(9H-fluorene-9-ylidene)-1-phenylethanone derivatives mediated by ceric ammonium nitrate. In the case of the reaction of 9-benzylidene-9H-fluorene with acyclic 1,3-dicarbonyl compounds, spiro 2-hydroxytetrahydrofuran fluorene derivatives were obtained. 相似文献
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Vijay Shankar Rangasamy Savitha Thayumanasundaram Jean-Pierre Locquet Jin Won Seo 《Ionics》2017,23(3):645-653
Among the various cathode materials explored for sodium-ion batteries (SIBs), NaMn0.33Ni0.33Co0.33O2, with a layered oxide structure, is a promising material due to its high theoretical capacity (240 mAhg?1). We have synthesized NaMn0.33Ni0.33Co0.33O2 using two different types of precursors, namely metal acetates and metal nitrates by the sol-gel method. XRD patterns confirm the formation of a stable phase of the material at 900 °C. Coupled TGA-FTIR analysis was used to optimize the calcination conditions and to understand the hydrolysis and condensation mechanism of the sol-gel precursors. FTIR spectra extracted at different temperatures reveal the polymer network-forming tendency of the acetate ligands whereas the polymerization is inhibited in the nitrate precursors. SEM analysis shows spherical and platelet morphologies of samples synthesized from nitrate and acetate precursors, respectively. Using in situ impedance and galvanostatic charge/discharge studies, we observed that the precursors used to synthesize the cathode material influence the electrochemical properties of the material, as in this case, where we observe a 20 % improvement in terms of capacity by using acetate precursors instead of nitrate precursors. 相似文献
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Savitha Thayumanasundaram Vijay Shankar Rangasamy Jin Won Seo Jean-Pierre Locquet 《Ionics》2018,24(5):1339-1347
We report the synthesis of Li2CoSiO4 by the sol-gel method and the preparation of a composite electrode by incorporating functionalized multi-walled carbon nanotubes (fn. MWCNTs) as conductive additive. XRD pattern of the composite confirms the structural stability of Li2CoSiO4 even after the addition of fn. MWCNTs. SEM images of the composite reveal the presence of conductive bridges formed by MWCNTs between the submicron-sized particles of Li2CoSiO4. The cyclic voltammograms of the composite cathode show redox peaks with higher current density than pure Li2CoSiO4 and the current density increases with increase in sweep rate. The diffusion coefficient of lithium has been improved by the addition of fn. MWCNTs from 1 × 10?14 to 8 × 10?14 cm2/s as calculated using Randles-Sevcik equation. The charge-discharge cycling performance of both pure Li2CoSiO4 and composite cathode has been discussed. 相似文献