石墨烯负载纳米粒子复合材料的研究进展

石墨烯是一种新型的碳纳米材料,因其独特的二维晶体结构和优异的性能,近年来成为各领域研究的热点.首先概述了石墨烯负载不同纳米金属粒子、纳米金属氧化物或氢氧化物复合材料近年来的研究进展和实际应用,然后提出了石墨烯负载纳米粒子复合材料的未来研究方向,并展望了其可能的应用前景.     

纳米纤维素/银纳米粒子的制备和表征

以纳米纤维素(NCC)为分散剂,硼氢化钠为还原剂还原硝酸银,化学还原法制备纳米纤维素/银纳米粒子。m(Ag)/m(NCC)=5%制备的纳米纤维素/银纳米粒子,X射线衍射分析结果表明,纳米纤维素/银纳米粒子中NCC和银纳米粒子相互混合并未改变各自的晶型,纳米纤维素/银纳米粒子中银纳米粒子的晶粒尺寸为11.87nm,与透射电子显微镜(TEM)所测银纳米粒子直径(10nm)相近;热重分析结果表明,纳米纤维素/银纳米粒子的热稳定性较纳米纤维素稍有下降。透射电子显微镜(TEM)分析、紫外光谱分析、固含量分析、机理分析和抑菌活性分析结果表明,m(Ag)/m(NCC)=3%时制备的纳米纤维素/银纳米粒子对大肠杆菌和金黄色葡萄球菌均有抑制作用,且银纳米粒子在纳米纤维素/银纳米粒子中分散较均匀。     

金属纳米粒子修饰的石墨烯加强铜基复合材料

利用镍纳米粒子修饰石墨烯(GPLs)制备石墨烯镍纳米粒子复合物(Ni-GPLs);将复合物作为增强相作用于Cu基体(NiGPLs-Cu),研究其力学性能;采用SEM、TEM、XRD、FT-IR和XPS等对Ni-GPLs进行表征。结果表明:Ni-GPLs由附着在GPLs上且分散均匀的镍纳米颗粒构成,镍离子通过化学还原在GPLs表面合成Ni-GPLs;含有体积分数为0.8%Ni-GPLs的Ni-GPL-Cu复合材料的极限抗拉强度(UTS)显著提高,比纯Cu的高出42%,大大提高Ni-GPLs-Cu的力学性能。     

纤维素基材料负载金属纳米粒子催化降解研究进展

由于金属纳米粒子具有高催化活性、反应选择性和易于制备等特点,其被认为是化学反应中的优异催化剂,但存在着高成本、难分离、易团聚、不可回收再利用等缺点。纤维素是迄今最丰富的可再生天然聚合物,广泛存在于高等植物、动物及细菌中,而又由于其高比表面积、较好的稳定性及化学可修饰性,因此纤维素基材料可以作为金属纳米粒子的良好载体。对近年来纤维素基材料负载金属纳米粒子催化剂的制备及催化性能进行了综述,以便有关科研人员了解多方位的有效尝试方法和探讨的途径。     

基于改性纳米纤维素的电化学储能材料的研究进展

纤维素是一种来源广泛、绿色友好的天然高分子材料。由各种物理化学手段从纤维素中提取出来的纳米纤维素(NC)拥有提取简单、高结晶度和高比表面积等优点,将其用于与其他材料复合时往往能激发出复合材料更大的潜力。基于纳米纤维素表面暴露出的大量羟基结构可以对其进行功能化改性,这对于进一步发挥纳米纤维素的潜力具有重大的意义。简要介绍了纳米纤维素的改性方法以及在电化学储能领域中的应用和展望。     

木质素基金属纳米粒子复合材料的制备及其应用研究进展

木质素是一种最丰富的芳香族天然高分子生物质资源,木质素纳米粒子既具有木质素原本特点,还具有纳米材料的纳米效应等特性,在众多功能材料领域具有很大的潜在应用价值,特别是作为绿色还原剂直接还原金属离子生成木质素基金属纳米粒子复合材料,被广泛应用于催化领域等.本文综述了木质素纳米粒子的制备及其在金属离子还原和金属纳米粒子负载的...     

碳纳米管和金属纳米粒子的异质连接研究进展

碳纳米管作为金属纳米粒子的载体材料,用于催化荆、纳米电子学、光学、纳米生物技术等领域.但碳纳米管与金属之间表面张力的差异显著,不利于金属纳米粒子附着.通过碳纳米管表面改性,利用功能基团可实现较好的异质连接.分析了碳纳米管与金属纳米粒子之间的异质连接及其在功能材料中的应用研究状况,探讨了解决碳纳米管/金属复合材料界面结合问题的各种方法,展望了异质连接技术的发展趋势.     

纳米纤维素的应用研究进展

纳米纤维素是一种新型的天然高分子材料,具有高结晶度、高强度等特殊的理化性质和优良的机械性能,其应用范围将越来越广泛。主要综述了纳米纤维素在酶固定化、生物传感、生物成像、医药及造纸工业等方面的应用,并对其发展前景进行了展望。     

无机纳米粒子/乳液复合材料的研究进展

无机纳米粒子/乳液复合材料是近几年发展起来的一种新型材料。本文中首先介绍了无机纳米粒子表面改性的原理和方法,然后总结了制备无机纳米粒子/乳液复合材料的方法及特点,最后对无机纳米粒子/乳液复合材料今后的发展提出一些见解。     

纤维素基金属纳米粒子复合催化剂的制备与应用

纤维素是一种来源广泛、比表面积大、多羟基且环境友好型的生物高分子材料,其水悬浮液可形成三维网络缠结结构,从而为具有催化活性的金属纳米粒子提供负载位点,使其均匀分散并固定于基底内部或表面构建复合催化剂材料,进而有效提高催化性能.本文综述了纤维素基金属纳米粒子复合催化剂的制备及应用的相关研究,重点介绍了不同纤维素基材料作为...     

Robust magnetic and electromagnetic wave absorption performance of reduced graphene oxide loaded magnetic metal nanoparticle composites

With the increasing demand for microwave absorbing materials, to develop a microwave absorber with a simple synthesis process is of great significance to the field of protection. Herein we have successfully loaded iron-cobalt-nickel oxide (FeCoNiO_x) onto the as-prepared polydopamine-reduced graphene oxide (PDA-rGO) through a two-step process. The preparation method has mild reaction conditions without high temperature and pressure compared with the traditional method, which is conducive to large-scale production. Based on effectively combining dielectric loss and magnetic loss mechanism, the obtained material possesses excellent electromagnetic waves absorbing performance with the minimum RL value of ?36.28 dB. The results proved that the composites can be endowed with various microwave absorption effects by the adjustion of different component ratios. In addition, the microwave absorption mechanism was dicussed in detail, and we believe that the results of our research have certain guiding significance for preparation of efficient microwave absorbers.     

Triptolide loaded solid lipid nanoparticle hydrogel for topical application

Triptolide (TP) has been shown to have anti-inflammatory, antifertility, antineoplastic, and immunosuppressive activity. However, its clinical usage is limited to some extent due to its poor water solubility and toxicity. In order to use innovative ways to administer TP and to overcome or alleviate its disadvantages, controlled-release delivery systems such as solid lipid nanoparticle(SLN(s)) have been developed. In the present paper we describe the preparation and some characterization of specialized delivery systems for TP. The transdermal delivery and anti-inflammatory activity were also evaluated. The results indicated that SLN could serve as an efficient promoter of TP penetrating into skin. Furthermore, different formulations were optimized in this study. The best formulation of SLN, consisted of tristearin glyceride, soybean lecithin, and PEG400MS, with a particle size of 123 ± 0.9 nm, polydispersity index (PI) of 0.19, and zeta potential of - 45 mV. When this SLN dispersion was incorporated into hydrogel, the nanoparticulate structure was maintained, and aggregation and gel phenomena of the particle could be avoided. The cumulative transdermal absorption rate in 12 h was 73.5%, whereas the conventional TP hydrogel was 45.3%. The anti-inflammatory effect is over two-fold higher than that of conventional TP hydrogel. Moreover, this SLN hydrogel consists of pharmaceutically acceptable ingredients, such as soybean lecithin and lipid, and the nanoparticle can improve safety and minimize the toxicity induced by TP.     

Radiation damping in metal nanoparticle pairs

The radiation damping rate of plasmon resonances in pairs of spherical gold nanoparticles is calculated. The radiative line width of the plasmon resonance indicates significant far-field coupling between the nanoparticles over distances many times the particle diameter. The radiation damping of the coupled particle-plasmon mode alternates between superradiant and subradiant behavior when the particle spacing is varied. At small particle spacings where near-field coupling occurs, the radiation damping rate lies far below that of an isolated particle.     

Femtosecond response of a single metal nanoparticle

The ultrafast nonlinear optical response of a single metal nanoparticle is investigated by combining a high-sensitivity femtosecond pump-probe setup with a spatial modulation microscope. Experiments are performed on 20 and 30 nm silver nanospheres, in situ characterized via their optical linear extinction spectrum. The measured transient response permits investigation of the electron-phonon energy transfer time in a single nanoparticle. Its dependence on the electronic temperature is quantitatively interpreted using the two-temperature model.     

Electrical field-flow fractionation for metal nanoparticle characterization

The potential of electrical field-flow fractionation (ElFFF) for characterization of metal nanoparticles was investigated in this study. Parameters affecting separation and retention such as applied DC voltage and flow rate were examined. Nanoparticles with different types of stabilizers, including citrate and tannic acid, were investigated. Changes to the applied voltage showed a significant influence on separation in ElFFF, and varying flow rate was used to improve plate heights in the experiments. For nanoparticles of a fixed size, the separation was based primarily on electrophoretic mobility. Particles with low electrophoretic mobility elute earlier. Therefore, citrate stabilized gold nanoparticles (-2.72 × 10(-4) cm(2) V(-1) s(-1)) eluted earlier than tannic acid stabilized gold nanoparticles (-4.54 × 10(-4) cm(2) V(-1) s(-1)) of the same size. In addition, ElFFF can be used for characterization of gold nanoparticles with different particle sizes including 10, 20, and 40 nm with a fixed stabilizing agent. For a specific separation condition, the separation of 10, 20, and 40 nm gold nanoparticles was clearly based on the particle size as opposed to the electrophoretic mobility, as the elution order was in order of decreasing mobility for 10 (-4.54 × 10(-4) cm(2) V(-1) s(-1)), 20 (-3.97 × 10(-4) cm(2) V(-1) s(-1)), and 40 (-3.76 × 10(-4) cm(2) V(-1) s(-1)) nm particles, respectively.     

Scaling-up metal nanoparticle production by transferred arc discharge

The number of applications and products containing metal nanomaterials has significantly increased over the past years. In order to address the upcoming demand for metal nanoparticles, new scale-up strategies are required. The scale-up of nanoparticle synthesis, especially for metals, is however very challenging. This study reports about a production facility with a new scale-up approach for pure metal nanoparticles. The scale-up approach is the parallelization of multiple transferred arcs in one reactor, which were previously individually optimized. Furthermore, a novel filtration and bagging system is introduced, which is designed to handle pyrophoric metal nanoparticles. It is shown that the production rate of the process scales linearly with the number of transferred arcs, while the particle size stays on the nanoscale.     

Modelling flow and filtration in liquid composite moulding of nanoparticle loaded thermosets

This paper presents analytical and numerical models of liquid moulding of hybrid composites. An 1-D analytical solution of Darcy’s problem, accompanied by nanoparticle filtration kinetics and conservation, has been developed. A non-linear finite difference model incorporating variations in permeability, porosity and viscosity as a function of local nanoparticle loading was formulated. Comparison of the two models allowed verification of their validity, whilst a mesh sensitivity study demonstrated the convergence of the numerical scheme. The limits of validity of the analytical solution were established over a range of infiltration lengths and filtration rates for different nanoparticle loadings. The analytical model provides an accurate and efficient approximation of through thickness infusion of hybrid composites, whereas use of the numerical scheme is necessary for accurate simulation of in-plane filling processes. The models developed here can serve as the basis of process design/optimisation for the production of hybrid composites with controlled distribution of nano-reinforcement.