碳纳米管/聚苯胺复合材料的制备及电性能

利用超声波将多壁碳纳米管(CNTs)分散于苯胺盐酸溶液体系中,以过硫酸铵((NH4)2S2O8)为氧化剂,原位聚合法制备碳纳米管/聚苯胺纳米复合材料(CNTs/PANI)。采用扫描电子显微镜(SEM)、傅立叶变换红外光谱(FT-IR)、四探针电导率测试仪对复合材料进行表面观察、结构测定和电性能表征。结果表明,复合材料为核-壳结构,碳纳米管和聚苯胺间存在相互作用,其电导率随碳纳米管含量的增加而增加。     

Three‐Dimensional Printing of Multifunctional Nanocomposites: Manufacturing Techniques and Applications

The integration of nanotechnology into three‐dimensional printing (3DP) offers huge potential and opportunities for the manufacturing of 3D engineered materials exhibiting optimized properties and multifunctionality. The literature relating to different 3DP techniques used to fabricate 3D structures at the macro‐ and microscale made of nanocomposite materials is reviewed here. The current state‐of‐the‐art fabrication methods, their main characteristics (e.g., resolutions, advantages, limitations), the process parameters, and materials requirements are discussed. A comprehensive review is carried out on the use of metal‐ and carbon‐based nanomaterials incorporated into polymers or hydrogels for the manufacturing of 3D structures, mostly at the microscale, using different 3D‐printing techniques. Several methods, including but not limited to micro‐stereolithography, extrusion‐based direct‐write technologies, inkjet‐printing techniques, and popular powder‐bed technology, are discussed. Various examples of 3D nanocomposite macro‐ and microstructures manufactured using different 3D‐printing technologies for a wide range of domains such as microelectromechanical systems (MEMS), lab‐on‐a‐chip, microfluidics, engineered materials and composites, microelectronics, tissue engineering, and biosystems are reviewed. Parallel advances on materials and techniques are still required in order to employ the full potential of 3D printing of multifunctional nanocomposites.     

Significance of Nanomaterials in Wearables: A Review on Wearable Actuators and Sensors

Together with the evolution of digital health care, the wearable electronics field has evolved rapidly during the past few years and is expected to be expanded even further within the first few years of the next decade. As the next stage of wearables is predicted to move toward integrated wearables, nanomaterials and nanocomposites are in the spotlight of the search for novel concepts for integration. In addition, the conversion of current devices and attachment‐based wearables into integrated technology may involve a significant size reduction while retaining their functional capabilities. Nanomaterial‐based wearable sensors have already marked their presence with a significant distinction while nanomaterial‐based wearable actuators are still at their embryonic stage. This review looks into the contribution of nanomaterials and nanocomposites to wearable technology with a focus on wearable sensors and actuators.     

Graphene‐Bonded and ‐Encapsulated Si Nanoparticles for Lithium Ion Battery Anodes

Silicon (Si) has been considered a very promising anode material for lithium ion batteries due to its high theoretical capacity. However, high‐capacity Si nanoparticles usually suffer from low electronic conductivity, large volume change, and severe aggregation problems during lithiation and delithiation. In this paper, a unique nanostructured anode with Si nanoparticles bonded and wrapped by graphene is synthesized by a one‐step aerosol spraying of surface‐modified Si nanoparticles and graphene oxide suspension. The functional groups on the surface of Si nanoparticles (50–100 nm) not only react with graphene oxide and bind Si nanoparticles to the graphene oxide shell, but also prevent Si nanoparticles from aggregation, thus contributing to a uniform Si suspension. A homogeneous graphene‐encapsulated Si nanoparticle morphology forms during the aerosol spraying process. The open‐ended graphene shell with defects allows fast electrochemical lithiation/delithiation, and the void space inside the graphene shell accompanied by its strong mechanical strength can effectively accommodate the volume expansion of Si upon lithiation. The graphene shell provides good electronic conductivity for Si nanoparticles and prevents them from aggregating during charge/discharge cycles. The functionalized Si encapsulated by graphene sample exhibits a capacity of 2250 mAh g^?1 (based on the total mass of graphene and Si) at 0.1C and 1000 mAh g^?1 at 10C, and retains 85% of its initial capacity even after 120 charge/discharge cycles. The exceptional performance of graphene‐encapsulated Si anodes combined with the scalable and one‐step aerosol synthesis technique makes this material very promising for lithium ion batteries.     

核壳结构纳米复合材料的研究进展

纳米粒子由于具有大量的潜在应用,近年来已引起人们极大的关注.通过制备具有核壳结构的纳米复合材料可以使其获得更多特殊的性质.综述了最近几年制备壳核结构纳米粒子的方法,根据其核、壳的不同材料分了4类,并对其中某些方法进行了比较,同时指出了目前该领域的应用前景、存在的不足和今后的研究发展方向.     

LDPE/EVA/蒙脱土熔融插层纳米复合体系稳态剪切流变行为

用平行板和毛细管流变仪测定并研究了具有剥离结构的低密度聚乙烯(LDPE)／乙烯-醋酸乙烯共聚物(EVA)／蒙脱土纳米复合材料熔体的稳态剪切流变行为。研究结果表明,蒙脱土含量较低的复合物熔体,在低剪切速率下,即出现剪切变稀现象；而在较高剪切速率下,填充物浓度对体系熔体的剪切粘度影响较小；与基体树脂相比较,蒙脱土的加入,使其熔体的非牛顿指数降低,粘流活化能略有增加。     

Synthesis, structure and properties of a novel hybrid bimodal network elastomer with inorganic cross-links: The case of silicone–nanocrystalline titania

We describe an innovative concept of synthesizing a novel hybrid bimodal network elastomer with high strength–high ductility combination involving utilization of functionalized nanocrystalline titania as short-chain cross-links between neighboring elastomer chains. This subject is germane both fundamentally and from an application viewpoint. Silicone rubber is selected as the model elastomer. The short-chain cross-links are acrylic acid functionalized nanocrystalline titania that are an integral component of bimodal network structure of the elastomer. To delineate and separate the effects of functionalization from nanoparticle effects, a relative comparison is made between silicone rubber–titania nanocomposite (i.e. containing dispersion of titania as a reinforcement filler) and silicone rubber–titania hybrid network elastomer (i.e. titania as short chain cross-links). An important finding is that the effect of functionalized titania present as short chain cross-links is far more significant than non-functionalized titania present as reinforcement filler, on mechanical behavior. This is presently ascribed to the double bonds introduced to nanocrystalline titania via functionalization with acrylic acid that provide active sites for the cross-linking reaction resulting in inorganic bridging chains. The basic physical mechanisms that govern elastic recovery in hybrid bimodal network elastomer with short chain cross-links of functionalized nanocrystalline inorganic particles are discussed. The hypothesis of the study described here is that the hybrid bimodal network elastomer with short chain cross-links of functionalized nanocrystalline inorganic particles modifies the unimodal long chain network elastomer with consequent increase in modulus and high strength–ductility combination.     

蒙脱土的酸化及有机化对聚氨酯/蒙脱土纳米复合弹性体材料性能的影响

利用本体聚合方法制备了聚氨酯/蒙脱土纳米复合材料。通过对蒙脱土进行酸化和有机化两步处理,发现酸化处理不仅能有效地扩大蒙脱土的片层间距,还能有效地防止蒙脱土在聚氨酯本体聚合时对异氰酸酯基三聚副反应的催化作用。利用DSC、TGA、XRD等手段对聚氨酯/蒙脱土纳米复合材料的力学性能、热性能、内部结构进行了表征,发现酸化及有机化蒙脱土在聚氨酯内部能形成纳米片层结构,提高了复合材料的力学性能。     

基于Au NPs-CeO2@PANI纳米复合材料固定化酶的葡萄糖生物传感器

制备了一种基于金纳米粒子(Au NPs)、氧化铈纳米颗粒(CeO2)和导电聚苯胺(PANI)的具有核壳结构的纳米复合材料(Au NPs-CeO2@PANI),利用该纳米复合材料和壳聚糖形成的复合膜成功实现了对葡萄糖氧化酶(GOD)的固定.采用透射电镜和X射线衍射对Au NPs-CeO2@PANI材料进行了表征.电化学方法研究了传感器性能,结果表明基于Au NPs-CeO2@PANI纳米复合材料修饰的葡萄糖生物传感器线性范围为6.2×10-6 mol/L～2.8×10-3 mol/L,响应时间为5 s,检测下限为1.0×10-6 mol/L;相同条件下Au NPs-CeO2@PANI纳米复合材料修饰的电极也显示出了比单一或二者复合的纳米材料修饰电极更优越的性能.