共轭导电高分子/纳米纤维素复合材料研究进展

以纳米纤维素为基体材料、共轭导电高分子为功能材料,制备的共轭导电高分子/纳米纤维素复合材料兼具共轭导电高分子良好的导电性能以及纳米纤维素易改性、易成膜、可降解等优良特性,由此而拓宽了二者的开发与应用范围,并促进了导电高分子复合材料的发展。综述了几种典型的共轭导电高分子/纳米纤维素复合材料的研究进展,介绍了聚苯胺/纳米纤维素复合材料、聚吡咯/纳米纤维素复合材料和聚噻吩/纳米纤维素复合材料的制备及应用。     

纳米结构聚苯胺及其复合气敏材料研究进展

综述了近十年来聚苯胺导电高分子及其复合物气敏材料的研究进展。重点介绍了纳米结构聚苯胺、聚苯胺与有机高分子复合材料、聚苯胺与纳米结构无机半导体或金属等复合材料的气敏响应特性及敏感机理。讨论了影响聚苯胺基纳米复合材料气敏性能的主要因素,包括复合材料的纳米结构、制备工艺,以及有机高分子,无机半导体及金属等复合材料和检测气体的性质等,提出这类高分子复合气敏材料今后发展的趋势与前景。     

纳米结构聚苯胺及聚苯胺纳米复合材料的研究进展

聚苯胺是目前研究最为广泛的导电高分子材料之一。综述了不同纳米结构聚苯胺及聚苯胺纳米复合材料的合成方法,并着重介绍了聚苯胺纳米复合材料在超级电容器、电化学生物传感器、锂离子电池等领域应用的最新进展,最后展望了聚苯胺纳米复合材料的应用前景。     

碳纳米管/导电高分子功能复合材料的合成与应用

碳纳米管/导电高分子复合材料由其优异的电学特性引起了研究者的广泛关注,主要总结了国内学者在碳纳米管表面修饰技术的基本原理;碳纳米管/导电高分子复合材料的合成方法;碳纳米管/导电高分子复合材料的电学相关应用的研究动态,展望了碳纳米管/导电高分子复合材料的可控合成与功能性应用之间的定量构效关系,针对制备高性能的碳纳米管/导电高分子复合材料提出了建议。     

磁性微粒-导电高分子纳米复合材料的研究进展

本文综述了近年来磁性微粒-导电高分子纳米复合材料的合成技术与材料性质,特别是其吸波性能的最新研究进展.     

PZT/CB/PVC压电导电高分子复合材料的吸声机理

基于压电导电原理,研制了一种新型吸声高分子复合材料,通过对PZT/CB/PVC高分子复合体系的压电性能、阻尼因子和吸声性能的测试分析,探讨了压电导电高分子复合材料体系中压电吸声途径的耗能机制,结论表明:导电相的添加,一定程度上提高了压电导电高分子复合材料的吸声性能.     

炭黑复合导电材料的导电机理

讨论了导电高分子材料的分类和性能特点,以及炭黑复合导电高分子材料的导电特性与机理,阐述了导电高分子材料的导电机理和影响因素,同时对导电复合材料未来的发展提出建议。     

高分子纳米复合材料用于骨骼再生

据报道，中科院长春应用化学研究所承担的国家“863”课题——智能型生物可吸收导电高分子纳米复合材料与电刺激定向诱导组织再生项目，近日通过了国家科技部组织的专家验收。     

纳米导电高分子材料结构特性和制备方法研究进展

纳米导电高分子不仅具有导电性能,而且具有纳米材料的特殊性能.综述了纳米导电高分子材料的结构特性、分类、制备方法及研究进展,并提出了未来的研究发展方向.     

高密度聚乙烯/纳米石墨导电纳米复合材料压敏特性研究

以高密度聚乙烯(HDPE)为基体,纳米石墨为导电填料,通过双辊混炼制备了具有良好压敏特性的导电纳米复合材料.研究了纳米石墨复合材料的电学性能及压敏性能,讨论了纳米石墨含量以及加压次数对导电复合材料压敏特性的影响.     

Conducting polymer/clay nanocomposites and their applications

This review aims at reporting on interesting and potential aspects of conducting polymer/clay nanocomposites with regard to their preparation, characteristics and engineering applications. Various conducting polymers such as polyaniline, polypyrrole and copolyaniline are introduced and three different preparation methods of synthesizing conducting polymer/clay nanocomposites are being emphasized. Morphological features, structure characteristics and thermal degradation behavior are explained based on SEM/TEM images, XRD pattern analyses and TGA/DSC graphs, respectively. Attentions are also being paid on conductive/magnetic performances as well as two potential applications in anti-corrosion coating and electrorheological (ER) fluids.     

Humidity-sensing properties of conducting polypyrrole-silver nanocomposites

We report here the humidity-sensing characteristics of conducting polypyrrole (PPY)-silver nanocomposites prepared by wet-chemical technique. Addition of silver into the conducting polymer network shows remarkable change in resistance with relative humidity (RH). The resistance of PPY-silver nanocomposites is found to increase with RH till a threshold value, above which the resistance tends to decrease. The threshold RH value is significantly reduced with the increase in silver concentration into the conducting polymer network. The modified metal–polymer interface and the associated interfacial water molecules play the critical role in determining the electrical transport and hence the humidity-response characteristics of the nanocomposites.     

Thermophysical and Electrical Properties of Nanocomposites Based on Ethylene–Vinylacetate Copolymer (EVA) Filled with Expanded and Unexpanded Graphite

Over the last few years, conducting polymer/graphite nanocomposites have attracted considerable interest because of their exceptional electrical, thermal, and mechanical properties. Polymeric nanocomposites prepared from high aspect ratio layered graphite nanofillers achieve significant improvements in thermophysical and electrical properties at low filler concentrations, compared to conventional composites, without a significant increase in density. In this work, various aspects of the electrical and thermophysical behavior of nanocomposites are presented based on the ethylene–vinylacetate matrix filled with nanostructured expanded graphite and standard, (nano)/micro-sized graphite.     

Positive Temperature Coefficient Effect of Polypropylene/Carbon Nanotube/Montmorillonite Hybrid Nanocomposites

Ternary polypropylene/multiwalled carbon nanotube/montmorillonite (PP/MWNT/MMT) nanocomposites were prepared by melt compounding of a ball-milled MWNT and MMT mixture in a Haake mixer at a screw rotation rate of 200 r/$hbox{min}$. The electrical conducting behavior of such hybrid composites was examined. The results showed that the conducting behaviors of PP/MWNT/MMT nanocomposites were strongly dependent on the MWNT and MMT contents. The percolation concentration of such hybrid nanocomposites was 1.0 wt% MWNT. Furthermore, percolating PP/1.0 wt% MWNT/MMT nanocomposites exhibited a positive temperature coefficient (PTC) effect. The PTC transition temperature can be regulated over a broader temperature range by varying the MMT contents. Hybridization of nanofillers provides a facile methodology to fabricate conducting polymer nanocomposites with tunable PTC transition temperatures.      

Synthesis,characterization and weight percent effect on humidity sensing properties of Polypyrrole/AlCeO3 (PPy/ACO) nanocomposites

Polypyrrole (PPy)/aluminum cerium oxide (ACO) nanocomposites with different weight percentages of the ACO nanoparticles in the matrix of PPy have been synthesized successfully. The addition of fillers in the conducting polymer makes significant changes in their electrical, chemical, mechanical and gas sensing properties. The exact amount of filler is one of the essential parameters to get the desired properties in the host polymer. So, the optimization of the percent weight of filler in the host conducting polymer is very much crucial. The structural and morphological studies were done by XRD, FTIR, SEM, and TEM. These experimental studies reveal that nanoparticles of Aluminum cerium oxide are dispersed uniformly in the PPy chains. The humidity sensing properties for different weight percent of nanocomposites were studied by using impedance analyzer in the frequency range from 100?Hz to 5?MHz and at relative humidity (% RH) variation from 30% RH to 90% RH. The graphs of impedance versus frequency for all nanocomposites showed a slightly linear dependence at all the frequencies over the entire humidity range. The complex impedance (cole-cole) graphs and the corresponding equivalent circuits were studied to understand the conduction phenomenon in nanocomposites. The conduction in pure PPy shows the contribution from grain and grain boundaries while all the nanocomposites show contribution only from grains. The lower weight percent nanocomposites exhibit better response compared to higher weight percent.     

Effect of fabrication process on electrical properties of polymer/multi-wall carbon nanotube nanocomposites

Polymer/carbon nanotubes nanocomposites were fabricated by an in situ polymerization process using multi-wall carbon nanotubes (MWNT) as filler in an epoxy polymer. Effects of curing process, mixing speed, mixing time, addition of ethanol, timing of hardener addition, etc., in the fabrication process on the electrical properties of nanocomposites have been investigated. In the fabrication process, the effective formation of macroscopic conducting network in matrix is most important to enhance the electrical properties of nanocomposites. It was found that the curing temperature and the mixing conditions are key factors in the fabrication process, which influence the formation of conducting network significantly. Therefore, careful design of these factors in the fabrication process is required to achieve high electrical performances of nanocomposites. The experimental percolation threshold of the resultant nanocomposites was around 0.1 wt%. Moreover, a statistical percolation model was built up to numerically investigate the percolation threshold. The experimental electrical conductivity increases from the percolation threshold following a percolation-like power law with the identified critical exponent t as 1.75.     

Recent advances in thermoelectric materials

Thermoelectric materials are crucial in renewable energy conversion technologies to solve the global energy crisis. They have been proven to be suitable for high-end technological applications such as missiles and spacecraft. The thermoelectric performance of devices depends primarily on the type of materials used and their properties such as their Seebeck coefficient, electrical conductivity, thermal conductivity, and thermal stability. Classic inorganic materials have become important due to their enhanced thermoelectric responses compared with organic materials. In this review, we focus on the physical and chemical properties of various thermoelectric materials. Newly emerging materials such as carbon nanomaterials, electronically conducting polymers, and their nanocomposites are also briefly discussed. Strategies for improving the thermoelectric performance of materials are proposed, along with an insight into semiconductor physics. Approaches such as nanostructuring, nanocomposites, and doping are found to enhance thermoelectric responses by simultaneously tuning various properties within a material. A recent trend in thermoelectric research shows that high-performance thermoelectric materials such as inorganic materials and carbon nanomaterials/electronically conducting polymer nanocomposites may be suitable for power generation and energy sustainability in the near future.     

Memory effect in a junction-like CdS nanocomposite/conducting polymer poly[2-methoxy-5-(2-ethylhexyloxy)1,4-phenylene-vinylene] heterostructure

The operation of a nonvolatile memory device is demonstrated using junction-like CdS nanocomposites embedded in a polymer matrix. The capacitance-voltage characteristics of Al/conducting polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene]/CdS nanocomposites in a polyvinyl alcohol matrix/indium tin oxide device exhibit hysteresis, which is attributed to the trapping, storage, and emission of holes in the quantized valence band energy levels of isolated CdS nanoneedles. The characteristics at different operating frequencies show that the hysteresis is due to trapping of charge carriers in CdS nanocomposites rather than in the interfacial states. The memory behavior in the inorganic/organic heterostructure is explained on the basis of a simple energy band diagram.     

1D/2D Carbon Nanomaterial‐Polymer Dielectric Composites with High Permittivity for Power Energy Storage Applications

With the development of flexible electronic devices and large‐scale energy storage technologies, functional polymer‐matrix nanocomposites with high permittivity (high‐k) are attracting more attention due to their ease of processing, flexibility, and low cost. The percolation effect is often used to explain the high‐k characteristic of polymer composites when the conducting functional fillers are dispersed into polymers, which gives the polymer composite excellent flexibility due to the very low loading of fillers. Carbon nanotubes (CNTs) and graphene nanosheets (GNs), as one‐dimensional (1D) and two‐dimensional (2D) carbon nanomaterials respectively, have great potential for realizing flexible high‐k dielectric nanocomposites. They are becoming more attractive for many fields, owing to their unique and excellent advantages. The progress in dielectric fields by using 1D/2D carbon nanomaterials as functional fillers in polymer composites is introduced, and the methods and mechanisms for improving dielectric properties, breakdown strength and energy storage density of their dielectric nanocomposites are examined. Achieving a uniform dispersion state of carbon nanomaterials and preventing the development of conductive networks in their polymer composites are the two main issues that still need to be solved in dielectric fields for power energy storage. Recent findings, current problems, and future perspectives are summarized.     

Quantum dot sensitized solar cell based on poly (3-hexyl thiophene)/CdSe nanocomposites

The optoelectronic properties of P3HT–CdSe nanocomposites prepared by insitu chemical oxidative polymerization were studied. CdSe QDs were synthesized by hot injection method using tri octyl phosphine oxide (TOPO) as capping ligand whereas the P3HT polymer was prepared by chemical oxidative polymerization. FTIR studies confirmed the regioregularity of the P3HT and revealed the chemical interaction of P3HT and CdSe in nanocomposite. Absorption studies showed blue shift for the nanocomposites as compare to pristine P3HT, the electron transfer from conducting polymer to the CdSe was detected by the measurements of quenching of photoluminescence from conducting polymer after the addition of semiconductor nano crystals which confirmed that an optimum amount of nanoparticles provide networking in hybrid composites. The optimal result for device prepared by P3HT–CdSe nanocomposites was open circuit voltage (V_oc) 0.5, short circuit current density (J_sc) 0.66, Fill factor (FF) 0.6855 and efficiency (η) 0.22%.