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Complex Optical and Thermal Studies on As-Synthesized Conducting Polythiophene
摘要： A series of conducting polythiophene (PTh) samples have been synthesized using an in situ chemical oxidative polymerization technique in aqueous solution. The characterization of the as-synthesized optimized sample has been carried out by Fourier transform infrared spectroscopy, x-ray diffraction and thermogravimetric–differential thermal analysis techniques. Also, the complex optical parameters of all the as-synthesized polymeric samples have been investigated by using ultraviolet–visible spectroscopy. The as-synthesized polymeric samples exhibited absorption around 220–280 nm. The optical band gap was found to ranges from 5.06 eV to 5.24 eV. The maximum optical conductivity for the sample with a stoichiometric ratio of thiophene to FeCl3 of 70:30 wt.% was found to be 5.973 9 108 S cm?1 at 280 nm. The experimental results reveal that the thermal and optical performance of conducting PTh can be dramatically enhanced for the sample with a stoichiometric ratio of thiophene to FeCl3 of 70:30 wt.%. The improved complex optical properties of as-synthesized samples of conducting PTh validate their potential utilization in optoelectronic devices.
关键词： thermal analysis,complex optical properties,Polythiophene
更新于2025-11-19 16:56:35
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Synthesis of luminescent polymers in the UV light region from dimethacrylate monomer using novel quinoline dyes
摘要： This study aims at thermal and morphological features, as well as the degree of conversion these luminescent polymers obtained using a dimethacrylate monomer, and quinoline dyes as photoinitiator. The photoinitiators provide a ?uorescent propriety to the ?nal polymer. Thermal properties such as thermal stability, steps of mass loss, and glass transition are obtained by thermogravimetry-differential thermal analysis and derivative thermogravimetric and differential scanning calorimetry. Using the mid-infrared spectroscopy, it is possible to calculate the degree of conversion/rate of polymerization; the data indicate that the quinoline derivatives could be used as photoinitiators in lower concentration (0.1%) resulting in solid rigid polymers with higher conversion (74.24, 71.81, 66.36, and 61.09%). The morphological characteristics of polymers are analyzed by scanning electronic microscopy. Finally, solid ultraviolet–visible (UV–vis) analysis shows a bathochromic shift, due to the stabilization of the molecules in the solid state, compared to liquid UV–vis analysis. ? 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47461.
关键词： thermal analysis,quinoline dyes,photopolymerization,luminescent polymers,high conversion
更新于2025-11-14 15:18:02
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Compositional dependence of properties in calcium substituted sodium borophosphate glasses containing $${\hbox {VO}}^{2+}$$ VO 2 + ions
摘要： Synthesis of calcium-substituted sodium borophosphate glasses with compositions xCaO ? (30 ? x)Na2O ? 35B2O3 ? 35P2O5 (x = 0, 2, 5, 7 and 10 mol%, abbreviated as CNVx) containing additional 1.0 mol% of V2O5 following a melt-quench method has been carried out. Different analytical techniques viz. wide angle X-ray diffraction (to con?rm non-crystalline nature), ultraviolet–visible spectroscopy (for optical band gap analysis), infrared absorption spectroscopy (for structural analysis) and differential thermal analysis (to evaluate characteristic temperatures) were employed to characterize the synthesized compositions. The optical band gap is calculated for both indirect allowed and indirect forbidden transitions. The values of the band gap decrease with increasing concentration of CaO (from 5 to 10 mol%) at the cost of Na2O. The cut-off wavelength and Urbach’s energy are determined from the optical absorption spectra and were related to the structural changes occurring in these glasses with an increase in CaO content. The results obtained from Fourier-transform infrared studies con?rm that V2O5 and CaO play the role of network modi?er oxides. Also, the signi?cant shifting in IR bands with an increase in CaO content in the glass matrix suggests the formation of a new boron–oxygen ring. From differential scanning calorimetry measurements it is observed that substitution leads to the increase in natural bond orbitals, high degree cross-linking and thus strengthens the glass network. Glass transition temperature (Tg) is found to increase from 483 to 522?C. Electrical and dielectric properties are analysed using dc conductivity and impedance spectroscopy. Using impedance spectroscopy, different dielectric parameters i.e. dielectric loss (ε(cid:4)), electrical modulus (M ?) and ac conductivity (σac) etc. are evaluated as a function of frequency, temperature and composition. The frequency dependence of impedance exhibits the non-Debye relaxation behaviour and the total conductivity obeys Jonscher’s power law.
关键词： Jonscher’s power law,impedance spectroscopy,Band gap,differential thermal analysis
更新于2025-11-14 14:48:53
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Theoretical Investigation of Thermal Effects in High Power Er <sup>3+</sup> /Yb <sup>3+</sup> - Codoped Double-Clad Fiber Amplifiers for Space Applications
摘要： In this paper, a multiphysics numerical model based on the spatial-dependent rate equations and 3-D non-homogeneous heat conduction model is used to investigate the performance of Er3t/Yb3t-codoped double-clad fiber amplifiers with respect to the constraints associated with space applications. The effects of fiber length, coating thickness, and core radius changes are analyzed. Furthermore, the impact of thermal heating due to the high power optical signals propagating along the fiber on the amplifier gain is examined. The temperature dependence of the refractive index, emission and absorption cross sections, as well as the radiation induced attenuation is derived and modeled. It is observed that the coating thickness affects the temperature distribution along the whole fiber length. Thicker coating mitigates the temperature variation along the fiber as well as it improves the temperature difference between the core center and the outer fiber surface. Moreover, larger core results in higher optical gain and shorter fibers. By numerical results, it is inferred that the thermal effects could strongly degrade the whole amplifier performance.
关键词： heat conduction,rare earth,fiber amplifier,thermal analysis
更新于2025-09-23 15:23:52
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Synthesis of water-soluble conjugated polymer, poly(N-3-sulfopropylaniline) and the study of its glucose sensing property
摘要： A water-soluble conjugated polymer, poly(N-3-sulfopropylaniline) (PSPA) with 7–10 controlled repeating units has been synthesized through oxidative polymerization of sulfopropylaniline (SPA) monomer, which is prepared by N-alkylation of aniline using 3-propane sultone. The glass transition temperature (Tg), thermal stability, molecular weight and size distribution of the synthesized polymer were investigated by DSC, TGA and MALDI TOFF respectively. The spectral (UV-Vis, PL, NMR, FTIR) analysis has been done to develop a facile colorimetric method to sense glucose (a biomarker of diabetes). The synthesized polymers could detect glucose up to nanomolar (10?9 M), which are 106 fold less than the level of a diabetic patient (4 × 10?3-9 × 10?3 M). It is also observed that the naked eye can sense up to decimolar (10?1 M) level. The polymerization process and the chemistry of colorimetric sensing are explained through spectral and cyclic voltammetry analysis. The polymerization and the sensing of glucose occurred through the electron transfer dependent color change processes.
关键词： Polymerization,Glucose sensing,Spectroscopy,Thermal analysis
更新于2025-09-23 15:23:52
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High frequency electromagnetic energy phenomena in chiral dielectric structures with distributed and localized conductive insertions
摘要： Chiral dielectric structures with conductive insertions have the tendency to peculiarly concentrate the electromagnetic energy, subject to their specific architecture. The study analyses the associated heating effect at high transmission levels at GHz frequency, for the applications related to electromagnetic shielding. The favorable shielding structure can suffer, in well defined situations, a mechanical stress and/or an acceleration of aging mechanisms.
关键词： Numerical analysis,Electrical properties,Honeycomb,Thermal analysis
更新于2025-09-23 15:22:29
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A hybrid perchlorate with a low band gap: Crystal structure, physicochemical characterization and Hirshfeld surfaces study
摘要： The anhydrous hybrid material (C6H10N2) (ClO4)2 has been synthesized by the slow evaporation method. X-ray diffraction on a single crystal shows that this compound crystallizes in the monoclinic system with the centrosymmetric space group P21/c. The 2D supramolecular network is stabilized by NeH/O interactions whereas the van der Waals contacts play a key role in the consolidation of the 3D packing as verified by Hirshfeld surface analysis in combination with 2D fingerprint plots. The 13C CP-MAS NMR spectrum is in agreement with the X-ray structure. DFT calculations allowed the attribution of the NMR peaks. FT-IR spectrum confirms the presence of various functional groups in the synthesized material. The thermal stability, phase transition and degradation, of this material has been studied using simultaneous TG-DTA. The gap between the frontier molecular orbitals is about 1.53 eV suggesting that the studied compound is a semiconducting material.
关键词： Crystal structure,Spectroscopic study: thermal analysis,Hirshfeld surfaces
更新于2025-09-23 15:22:29
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Structural investigation of oxygen stoichiometry during thermocycles in PMN-28PT
摘要： The current research focuses on the role of oxygen partial pressure on structure and phase transitions of (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 with x ? 0.28 (PMN-28PT). The changes in oxygen content have been traced through weight gain/loss during 160 cycles between 250 and 300 (cid:2)C. The structural phase transitions have been investigated by in-situ high temperature powder X-ray diffraction and high temperature Raman spectroscopy. The variations in oxygen content in PMN-28PT result in structural changes and have a signi?cant effect on electrical impedance. It is suggested that bonding between oxygen and Ti and Pb atoms in the perovskite structure of PMN-28PT can be controlled by low oxygen partial pressure heat treatment.
关键词： Crystal structure,Phase transitions,Oxide materials,Thermodynamic properties,Thermal analysis
更新于2025-09-23 15:22:29
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Thermal analysis and optimization of air trench structures for thermally tunable devices
摘要： Thermally tunable devices are important building blocks of photonic integrated circuits for optical fiber communication and sensing applications. To increase their tuning efficiency, an air trench structure has been introduced to the devices. By using finite element method, the distributions of temperature, stress and displacement of the waveguide are studied. After optimization, under the temperature rise of 70 oC, the maximum values of temperature difference, stress and displacement are smaller than 10% of the temperature rise, allowable stress and 0.002% of the waveguide length, respectively. This optimized air trench structure is desired for thermally tunable devices reaching low power consumption, high temperature uniformity and mechanical stability.
关键词： thermal analysis,air trench structure,thermally tunable device
更新于2025-09-23 15:22:29
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Synthesis of Cyanate Esters Based on Mono-O-Methylated Bisphenols with Sulfur-Containing Bridges
摘要： We described a synthetic approach to bisphenol-based monocyanate esters based on mono-O-methylation of parental bisphenols followed by cyanation of the residual phenolic hydroxyl. Structures of the synthesized compounds were determined by the application of IR, NMR 1H and 13C spectroscopies, EI and MALDI mass spectrometry, and purity of the final product was controlled by HPLC. We showed that stability of the cyanate esters depends on the nature of the bridging group. Temperature range of thermally initiated cyclotrimerization of synthesized monocyanate ester, as well as reaction enthalpy, was determined by differential scanning calorimetry (DSC).
关键词： cyanate resins,bisphenols,curing,Mitsunobu reaction,aryl cyanates,cyanate esters,thermal analysis
更新于2025-09-23 15:22:29