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排序方式: 共有1766条查询结果,搜索用时 31 毫秒
1.
In the pursuit to enlarge the library of polyimide materials for energy applications, new polyimide/MWCNTs composite films have been developed by MWCNTs-assisted polycondensation reaction of a hydroxyl and triphenylmethane-containing diamine with benzophenone tetracarboxylic dianhydride targeting to highlight their electrical storage capability as flexible electrodes in micro-supercapacitors (mSCs). The Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance, UV–vis, fluorescence, and Raman spectroscopies were used to demonstrate the evolution of interfacial interactions between MWCNTs and the precursors (diamine monomer and intermediate polyamidic acid) and polyimide matrix that proved to be the origin of MWCNTs homogeneous dispersion. Thus, composite films incorporating 1, 3, 5, and 10 w.t.% MWCNTs were obtained and thoroughly investigated with regard to their morphology, mechanical behavior, thermal stability, and electrical conductivity. The electrochemical performance of these composites was first analyzed in a classical three-electrode cell by cyclic voltammetry and galvanostatic charge-discharge in both aqueous and organic electrolyte systems. By far, the best electrical storage capacity was obtained with the composite polyimide film containing 10% MWCNTs that was further used as both active material and current collector in a flexible symmetric mSC realized by a straightforward and low-cost procedure. In the attempt to better exploit the advantages of this composite film, it was layered with a graphite-containing paint and tested as an electrode in a flexible mSC, which provided satisfactory results. To our knowledge, this is the first report on the electrical charge storage capability of a polyimide/MWCNTs free-standing film as a flexible electrode in mSCs, which do not require time- and resource-consuming processing steps. 相似文献
2.
Poly(ε-caprolactone) (PCL) composites filled by multi-walled carbon nanotubes (MWCNTs) which was non-covalently modified by the combined surfactants of poly(sodium 4-styrenesulfonate) and cetyltrimethyl-ammonium bromide (PSS-CTAB) were fabricated via simple solution precipitation method. PCL/MWCNTs composites provided with the low procolation threshold (0.4?wt%) and high electrical conductivity due to good dispersion of MWCNTs. And the excellent mechanical properties and enhanced thermal stability were also obtained with the addition of modified MWCNTs. In addition, all PCL composites showed significantly enhanced crystallization with increasing the MWCNTs contents, which demonstrated that the MWCNT-induced crystallization of PCL could effectively regulate the properties of composites. In a word, introducing non-covalent functionalized MWCNTs in the polymer system was a promising way for developing excellent conductive composites. 相似文献
3.
Xiangchun Xuan 《Electrophoresis》2019,40(18-19):2484-2513
Microfluidic devices have been extensively used to achieve precise transport and placement of a variety of particles for numerous applications. A range of force fields have thus far been demonstrated to control the motion of particles in microchannels. Among them, electric field‐driven particle manipulation may be the most popular and versatile technique because of its general applicability and adaptability as well as the ease of operation and integration into lab‐on‐a‐chip systems. This article is aimed to review the recent advances in direct current (DC) (and as well DC‐biased alternating current) electrokinetic manipulation of particles for microfluidic applications. The electric voltages are applied through electrodes that are positioned into the distant channel‐end reservoirs for a concurrent transport of the suspending fluid and manipulation of the suspended particles. The focus of this review is upon the cross‐stream nonlinear electrokinetic motions of particles in the linear electroosmotic flow of fluids, which enable the diverse control of particle transport in microchannels via the wall‐induced electrical lift and/or the insulating structure‐induced dielectrophoretic force. 相似文献
4.
A comparative study has been carried on the role of balanced magnetron (BM) and unbalanced magnetron (UBM) sputtering processes on the properties of SnO2 thin films. The oxygen partial pressure, substrate temperature and deposition pressure were kept 20%, 700 °C and 30 mTorr, respectively and the applied RF power varied in the range of 150–250 W. It is observed that the UBM deposition causes significant effect on the structural, electrical and optical properties of SnO2 thin films than BM as evidenced by X-ray diffraction, C-V, Spectroscopic Ellipsometer and Photoluminescence measurements. The value of band gap (Eg) of the films deposited at 150 W in UBM is found as Eg = 3.83 eV which is much higher than the value of Eg = 3.69 eV as observed in BM sputtering indicating that UBM sputtering results in good crystalline quality. Further, the C-V measurements of SnO2 thin films deposited using UBM at high power 250 W show hysteresis with large flat band shift indicating that these thin films can be used for the fabrication of memory device. The observed results have been attributed to different mechanisms which exist simultaneously under unbalanced magnetron sputtering due to ion bombardment of growing SnO2 thin film by energetic Ar+ ions. 相似文献
5.
Nikita O. Shaparenko Nikolay B. Kompan'kov Marina G. Demidova Alexander I. Bulavchenko 《Electrophoresis》2020,41(18-19):1592-1599
The structure and conductivity of AOT (sodium bis(2-ethylhexyl) sulfosuccinate) solutions (2.5 × 10−4–2.5 × 10−1 M) in n-hexadecane-chloroform mixture at the chloroform concentration from 50 to 100 vol% were studied. The diffusion ordered spectroscopy NMR study revealed that in the indicated range, the observed hydrodynamic diameter of micelles depends only on the AOT concentration and does not depend on the chloroform content. Molar fractions of free AOT molecules and those aggregated into micelles were calculated using the Lindman's law: at concentrations above 2.5 × 10−1 М, the solutions contain mostly the micelles, whereas at concentrations below 2.5 × 10−4 M, the solutions contain AOT molecules. The transition region contains both the AOT molecules and the micelles. Conductivity measurements were used to determine free charge carriers in the bulk of solutions and their contributions to conductivity. 相似文献
6.
《Physics letters. A》2020,384(30):126786
Using the complex dielectric permittivity measurements, in the frequency range 20 Hz – 2 MHz and at temperatures between (25–70) ∘C, the polarizability (α), the electric modulus (M) and the electrical conductivity (σ), of a ferrofluid sample, were determined. The results enabled the computation of the thermal activation energy of electrical conduction, the obtained value being approximately equal, at 0.15 eV. By eliminating the losses arising from electrical conduction, we highlighted the existence of a Schwarz type dielectric relaxation, in the sample, at the frequency above 5 kHz. These results allowed, for the first time, the evaluation of the mechanical mobility, u, of the ions on the particle surface, resulting in a value of, m/s N. Knowledge of macroscopic and microscopic electrical properties is useful in explaining the dielectric polarization mechanisms and relaxation processes of ferrofluids, and also in the use of ferrofluids in technological and biomedical applications. 相似文献
7.
PANI/MWCNT-CdS nanocomposites with different content of CdS wt.% has been synthesized by the chemical oxidative in-situ polymerization reaction of aniline in the presence of multi-walled carbon nanotubes (MWCNT). TEM, XRD, FTIR, and TGA studies were done for the structural and thermal characterization of the samples respectively. The particle size of CdS nanoparticles distributes in between 2.7 and 4.8 nm. XRD spectrum reveals that the co-existence of MWCNT, CdS in PANI matrix, where CdS forms a hexagonal structure. TGA result shows that nanocomposite becomes more thermally stable with the increase in CdS content. The dc electrical transport property of PANI/MWCNT-CdS nanocomposites has been investigated within a temperature range 77 ≤ T ≤ 300 K. The dc conductivity follows a 3D variable range hopping (VRH) model. A large magnetoconductivity change (19%) is observed for 2 wt% CdS content in PANI/MWCNT-CdS, which is explained by the wave function shrinkage model. 相似文献
8.
Dr. Wei-Hua Deng Prof. Qiao-Hong Li Jie Chen Chuan-Zhe Wang Dr. Zhi-Hua Fu Dr. Xiao-Liang Ye Prof. Guan-E Wang Prof. Gang Xu 《Angewandte Chemie (International ed. in English)》2023,62(31):e202305977
The electronic conductivity (EC) of metal–organic frameworks (MOFs) is sensitive to strongly oxidizing guest molecules. Water is a relatively mild species, however, the effect of H2O on the EC of MOFs is rarely reported. We explored the effect of H2O on the EC in the MOFs (NH2)2-MIL-125 and its derivatives with experimental and theoretical investigations. Unexpectedly, a large EC increase of 107 on H2SO4@(NH2)2-MIL-125 by H2O was observed. Brønsted acid–base pairs formed with the −NH2 groups, and H2SO4 played an important role in promoting the charge transfer from H2O to the MOF. Based on H2SO4@(NH2)2-MIL-125, a high-performance chemiresistive humidity sensor was developed with the highest sensitivity, broadest detection range, and lowest limit of detection amongst all reported sensing materials to date. This work not only demonstrated that H2O can remarkably influence the EC of MOFs, but it also revealed that post-modification of the structure of MOFs could enhance the influence of the guest molecule on their EC to design high-performance sensing materials. 相似文献
9.
Pei Chen Xi Su Chuanzhe Wang Dr. Guang Zhang Dr. Ting Zhang Prof. Gang Xu Prof. Long Chen 《Angewandte Chemie (International ed. in English)》2023,62(40):e202306224
The emergence of two-dimensional conjugated metal–organic frameworks (2D c-MOFs) with pronounced electrical properties (e.g., high conductivity) has provided a novel platform for efficient energy storage, sensing, and electrocatalysis. Nevertheless, the limited availability of suitable ligands restricts the number of available types of 2D c-MOFs, especially those with large pore apertures and high surface areas are rare. Herein, we develop two new 2D c-MOFs (HIOTP-M, M=Ni, Cu) employing a large p-π conjugated ligand of hexaamino-triphenyleno[2,3-b:6,7-b′:10,11-b′′]tris[1,4]benzodioxin (HAOTP). Among the reported 2D c-MOFs, HIOTP-Ni exhibits the largest pore size of 3.3 nm and one of the highest surface areas (up to 1300 m2 g−1). As an exemplary application, HIOTP-Ni has been used as a chemiresistive sensing material and displays high selective response (405 %) and a rapid response (1.69 min) towards 10 ppm NO2 gas. This work demonstrates significant correlation linking the pore aperture of 2D c-MOFs to their sensing performance. 相似文献
10.
Keming Song Xiang Wang Zhengkun Xie Zhiwei Zhao Zhe Fang Zhengfeng Zhang Jun Luo Pengfei Yan Zhangquan Peng Weihua Chen 《Angewandte Chemie (International ed. in English)》2023,62(10):e202216450
Solid-electrolyte interphase (SEI) seriously affects battery's cycling life, especially for high-capacity anode due to excessive electrolyte decomposition from particle fracture. Herein, we report an ultrathin SEI (3–4 nm) induced by Cu+-tailored double electrical layer (EDL) to suppress electrolyte consumption and enhance cycling stability of CuS anode in sodium-ion batteries. Unique EDL with SO3CF3-Cu complex absorbing on CuS in NaSO3CF3/diglyme electrolyte is demonstrated by in situ surface-enhanced Raman, Cyro-TEM and theoretical calculation, in which SO3CF3-Cu could be reduced to CuF2-rich SEI. Dispersed CuF2 and F-containing compound can provide good interfacial contact for formation of ultrathin and stable SEI film to minimize electrolyte consumption and reduce activation energy of Na+ transport. As a result, the modified CuS delivers high capacity of 402.8 mAh g−1 after 7000 cycles without capacity decay. The insights of SEI construction pave a way for high-stability electrode. 相似文献