多酸-纳米粒子复合物的研究进展

多酸-纳米粒子复合物既具有多酸(POMs)多样的尺寸、可调节的多功能结构、丰富的组成、高的电荷密度及可逆的氧化还原等特性,同时又具有纳米粒子的声、光、电、磁、热、力学等特性.多酸-纳米粒子复合物有望被广泛运用到生物催化、电催化、光催化、生物传感和医药化学等领域.本文作者主要对多酸-纳米粒子复合物的合成方法和应用进行评述,并对今后的发展趋势进行展望.     

纳米粒子与细胞相互作用的力学-化学偶联研究进展

纳米粒子在生物医学和大气环境领域的广泛研究使得其生物安全性越来越受到重视。目前已经有许多研究关注纳米粒子与细胞的相互作用及细胞毒性问题。本综述从细胞力学-化学偶联的角度总结了近五年来有关纳米粒子与细胞相互作用的研究进展。首先介绍了与细胞力学-化学偶联性质相关的分子基础以及目前检测细胞机械性质的纳米技术,然后重点讨论了纳米粒子对细胞粘附、骨架、刚度和迁移性质的影响。在此基础上,进一步指出了纳米生物力学-化学偶联的挑战与展望。     

纳米金粒子/高分子复合物

纳米金粒子/高分子复合物由于其独特的光、电性能引起了材料工作者的关注.本文介绍了纳米金粒子的制备方法及其高分子复合物的制备过程和原理, 着重综述了纳米金/智能高分子复合物的研究进展.     

金纳米粒子与单链DNA的相互作用

研究了金纳米粒子与单链DNA在不同pH值时的相互作用以及金纳米粒子与不同碱基序列单链DNA的相互作用. 结果表明, 在pH为12.6的强碱性条件下, 单链DNA能使金纳米粒子稳定分散在溶液中; 在pH为1.4的强酸性条件下, 单链DNA能保护金纳米粒子不发生融合, 而只发生团聚, 且团聚现象具有可逆性. 不同寡核苷酸对金纳米粒子的亲和力按poly dA>poly dC>poly dT的顺序依次减弱. 单链DNA对纳米金的保护作用强度与单链DNA的长度成正比.     

用于制备聚氨酯纳米复合物的高岭石粒子的表征

Clay such as kaolinite， is commonly used as an additive to modify the thermal properties of polymer. In this paper， the morphology， composition， shape and structure of kaolinite was characterized by various advanced techniques. The TEM/ EDX data showed that the kaolinite had a larger particle size and a Si/Al ratio of 1.8. The individual particle of kaolinite was a single crystalline. TEM also showed that these particles were always stacked together due to the presence of electrostatic cohesive energy and hydrogen bond between plaletes. The PAS-FTIR spectra showed that no absorbance of hydroxyl group for hydration water in hydrogen bond region or at 1650cm^-1 was observed at room temperature. It meant a little ability to adsorb water for kaolinite particle. Kaolinite clay also showed no change for its PAS-FTIR spectra with increasing temperature. The TGA results revealed that kaolinite almost doesn′t lose weight at 60℃ due to loss of dehydration of absorbed water， however， it will decomposed around 510℃ and lose its hydroxyl functional group in the form of water (dehydroxylation). The result is consistent with that of PAS-FTIR analysis. This suggests that the structural hydroxyl group on the surface of individual kaolinite clay particle is very stable below 500℃， and the kaolinite composed polymer could be got by the reaction of its stable structural hydroxyl group with isocynate group of polyurethane prepolymer.     

无机纳米粒子填充聚合物的研究进展

对纳米粒子的历史、结构及特性作了简要介绍，着重介绍了纳米粒子的表面处理及其在填充了聚合物方面的应用开发。     

聚苯胺/金属纳米粒子复合物的制备及性能

基于国内外最新研究文献及本课题组研究工作,从发展历史、制备方法、多功能性方面系统综述了近年来发展起来的聚苯胺/金属纳米粒子复合物。在聚苯胺基体中引入金属纳米粒子的方法可归纳为3大类：原位复合法、直接共混法和层层自组装法。所形成的有机聚苯胺和无机金属杂化复合物不仅能保留各自原有的特异性能,而且二组分之间还存在着相互协同作用,能够极大地提升基体聚苯胺材料的性能,电导率最高可提高100倍,电氧化催化电流最高可提高10倍。分散在聚苯胺膜中的极少量铂微粒就能使不锈钢板的腐蚀电位稳定在钝化区域。聚苯胺/金属纳米粒子复合物所表现出的突出的固有电导性、优异的反应催化性和极强的金属防腐性,使其跻身于为数不多的新型高性能复合材料之列,显示出了诱人的应用前景。     

聚合物纳米粒子的结构和性能对胞吞和细胞功能的影响

随着纳米医学的发展,越来越多的聚合物纳米粒子被用作荧光探针和药物或基因的载体,在生物分析、检测以及药物传输和基因治疗等领域得到应用。细胞的胞吞是细胞将细胞外基质、病毒、微组织或纳米粒子运送到细胞内部的一个重要生理过程。研究细胞对纳米粒子的胞吞,有助于从细胞层次上理解生命现象,掌握细胞内治疗的机理。本文综述了近几年来细胞和聚合物纳米粒子之间相互作用的最新研究结果。首先介绍了用于胞吞研究的常用聚合物纳米粒子体系及其功能化方法,尤其是荧光探针的复合与表面修饰。进而介绍了细胞和聚合物纳米粒子之间相互作用的基本过程,包括聚合物纳米粒子在细胞转运过程中的驱动力、细胞内转运过程、在细胞中的分布及其细胞毒性。对影响聚合物纳米微粒胞吞的因素如纳米粒子浓度、共培养时间、纳米粒子性能（形状、粒径、电荷和PEG修饰）、细胞类型和培养条件等进行了总结。最后重点介绍了用于受体介导细胞胞吞的聚合物纳米粒子体系,指出了目前研究工作中的不足及未来发展方向。     

纳米金粒子与R-藻红蛋白的相互作用

以NaBH4为还原剂, 采用化学还原法制备了纳米金溶胶, 发现以pH=7的金前驱液还原得到的纳米金粒子具有最强的紫外吸收(525 nm), 当以聚乙烯吡咯烷酮(PVP)为稳定剂时, 此吸收紫移到510 nm. TEM观察金粒子大小为5~8 nm. PVP、聚乙烯醇(PVA)和吐温-80等能较好地稳定纳米金粒子, 而十二烷基苯磺酸钠、PEG-1000和OP乳化剂等则没有稳定作用. 以紫外-可见光谱(UV-Vis)、X光荧光光谱(XRF)、透射电子显微镜(TEM)等研究了纳米金粒子与R-藻红蛋白的相互作用, 发现R-藻红蛋白本身对纳米金粒子具有良好的稳定作用. 当R-藻红蛋白与纳米金粒子共存时, R-藻红蛋白所具有的538 nm吸收带强度有所增强, 并发生紫移, 同时578 nm的荧光强度也明显减弱, 这表明R-藻红蛋白与纳米金粒子的相互作用对R-藻红蛋白的空间结构产生了影响, 导致位于R-藻红蛋白外缘藻红素发色团(PEB)的微环境发生了改变. 凝胶柱层析及分光光度分析结果进一步证实了金纳米粒子与藻红蛋白存在明显的相互作用, 这种相互作用可能与藻红蛋白分子中所包含的氨基基团有关.     

智能聚合物包覆的金纳米粒子*

本文综述了智能聚合物包覆的金纳米粒子的研究进展,重点介绍了智能聚合物包覆金纳米粒子的制备方法,包括原位合成法、配体置换法、表面引发聚合法和表面接枝聚合法等,以及智能聚合物包覆的金纳米粒子的智能响应类型,如温度敏感型、pH敏感型、pH/电解质双重敏感型、pH/温度双重敏感型、溶剂敏感型等。     

Statistical Analysis of Polymer Nanocomposites for Mechanical Properties

Epoxy resins, due to their high stiffness, ease of processing, good heat, and chemical resistance obtained from cross-linked structures, have found applications in electronics, adhesives coatings, industrial tooling, and aeronautic and automotive industries. These resins are inherently brittle, which has limited their further application. The emphasis of this study is to improve the properties of the epoxy resin with a low-concentration (up to 0.4% by weight) addition of Multi-Walled Carbon Nanotubes (MWCNTs). Mechanical characterization of the modified composites was conducted to study the effect of MWCNTs infusion in the epoxy resin. Nanocomposites samples showed significantly higher tensile strength and fracture toughness compared to pure epoxy samples. The morphological studies of the modified composites were studied using Scanning Electron Microscopy (SEM).     

聚合物纳米复合体系中聚合物结构及动力学研究进展

从计算模拟及实验角度系统总结了聚合物结构、聚合物构象、聚合物扩散及聚合物多尺度动力学的研究进展,阐述了各影响因素及其变化规律,并对聚合物动力学的未来研究进行了展望.     

Network Polymer Properties Engineered Through Polymer Backbone Dispersity and Structure

Dispersity (Ð or M_w/M_n) is an important parameter in material design and as such can significantly impact the properties of polymers. Here, polymer networks with independent control over the molecular weight and dispersity of the linear chains that form the material are developed. Using a RAFT polymerization approach, a library of polymers with dispersity ranging from 1.2—1.9 for backbone chain-length (DP) 100, and 1.4—3.1 for backbone chain-length 200 were developed and transformed to networks through post-polymerization crosslinking to form disulfide linkers. The tensile, swelling, and adhesive properties were explored, finding that both at DP 100 and DP 200 the swelling ratio, tensile strength, and extensibility were superior at intermediate dispersity (1.3—1.5 for DP 100 and 1.6—2.1 for DP 200) compared to materials with either substantially higher or lower dispersity. Furthermore, adhesive properties for materials with chains of intermediate dispersity at DP 200 revealed enhanced performance compared to the very low or high dispersity chains.     

Ethylene-Octene Copolymer-Nanosilica Nanocomposites: Effects of Epoxy Resin Functionalized Nanosilica on Morphology,Mechanical, Dynamic Mechanical and Thermal Properties

A comparative study of the structural, thermal, mechanical and thermomechanical properties of ethylene-octene copolymer 1

1 Ethylene-octene copolymer is produced using Dow's INSITETM ™ constrained geometry catalyst and process technology. ENGAGE the trade name of this copolymer.

(mPE) 2

2 This copolymer will be represented as mPE .

nanocomposites synthesized with pure nanosilica (NS) and nanosilica-functionalized with diglycidyl ether of bisphenol-A (ENS) has been reported. These nanocomposites were prepared using “melt mixing” method at a constant loading level of 2.5 wt. %. The effects of pure nanosilica (NS) and epoxy resin-functionalized-nanosilica (ENS) on the above mentioned properties of ethylene-octene copolymer were analyzed by wide-angle-x-ray diffractometer (WAXD), transmission electron microscope (TEM), thermo gravimetric analyzer (TGA), differential scanning calorimeter (DSC), dynamic mechanical analyzer (DMA) and scanning electron microscope (SEM). TEM studies have shown a better dispersion of nanoparticles in case of ethylene-octene copolymer-epoxy resin-functionalized-nanosilica nanocomposite (mPE-ENS) than that of ethylene-octene copolymer-nanosilica nanocomposite (mPE-NS). The tensile tests show that organic modification of nanosilica particles brings up an appreciable increase in yield strength, ultimate tensile strength and elongation at break of the polymer. DMA studies have shown an increase in the storage modulus and glass transition temperature for mPE-ENS with respect to mPE-NS. Further, the TGA results have shown a higher thermal stability for mPE-ENS in comparison to mPE-NS.     

八苯基笼型倍半硅氧烷的官能化及其在高分子纳米复合材料中的应用

笼型倍半硅氧烷（POSS）是具有独特分子结构的有机硅化合物,无机硅氧骨架核心为其提供良好的硬度和热稳定性,外围有机基团可增强与聚合物基体间的相容性,以它为前驱体可以制备分子级分散的有机／无机纳米高分子杂化材料。近年来,全芳香结构的八苯基笼型倍半硅氧烷因其高的耐热性和官能化方法的多样性尤其得到关注。本文重点综述了八苯基笼...     

聚丙烯/PMMA/CaCO3纳米复合材料的制备、结构与力学性能

分别将经不同表面处理的纳米碳酸钙粒子与聚合物PP共混,制备PP／CaCO3和PP／PMMA／CaCO3纳米复合材料。用TEM观察了表面处理后纳米粒子的粒径与分散情况,发现复合粒子分散较均匀。用DSC与WAXD研究了复合材料的结晶行为,发现原位聚合制备的PMMA／CaCO3纳米复合粒子与PP共混后,PP有异相成核作用,出现了不稳定的PPβ晶型。PP／PMMA／CaCO3纳米复合材料力学性能有大幅度的提高。     

Modeling of Polymer Structure and Conformations in Polymer Nanocomposites from Atomistic to Mesoscale: A Review

Over the past two decades polymer nanocomposites have received tremendous interest from industry and academia due to their advanced properties comparative to polymer blends. Many computational studies have revealed that the macroscopic properties of polymer nanocomposites depend strongly on the microscopic polymer structure and conformations. In this article we review computer simulation studies of the fundamental problem of homopolymers structure and dimensions in nanocomposites containing bare or grafted spherical or rod nanoparticles. Experimentally, there is controversy over whether the addition of nanoparticles in a polymer matrix can perturb the polymer chains.     

Barrier and Mechanical Properties of Poly(caprolactone)/organoclay Nanocomposites

In this study, biodegradable poly(caprolactone) (PCL) hybrids with two types of organoclays: Cloisite 30B (30B) and Cloisite 93A (93A) have been prepared by melt mixing and their barrier performance to air permeation and mechanical properties were investigated. The hybrids of PCL/30B were found to be nanocomposites resulted from the strong interaction between organic modifier of 30B and PCL and those of PCL/93A were microcomposites. The barrier performance of PCL/30B nanocomposite film to air permeation was much more improved than pure PCL and PCL/93A microcomposites at low organoclay concentration. With the increase of organoclay content the permeability coefficient was also increased that could attributed to the extra tortuous pathway for gas permeation caused by organoclay exfoliation. The barrier behaviour of PCL/30B nanocomposites could be approximately described by a theoretical model developed for composites. The mechanical properties measurements showed that the reinforcement of organoclay 30B in nanocomposites is more significant than 93A in microcomposites. Both tensile modulus and tensile strength were increased in PCL/30B nanocomposites even at at low amount of organoclay without much loss of strain at break as compared to pure PCL. The significant improvements in both barrier and mechanical properties in PCL nanocomposites could be attributed to the fine dispersion state of organoclay 30B platelets in PCL matrix and the strong interaction between organic modifier of 30B and matrix molecules.     

Effect of Molybdenum Disulfide Exfoliation Conditions on the Mechanical Properties of Epoxy Nanocomposites

In this work, the MoS2 fillers were prepared through chemical exfoliation method and used as fillers to fabricate epoxy (EP)/MoS2 nanocomposites. The effects of molybdenum disulfide (MoS2) intercalation conditions on the properties of EP/MoS2 nanocomposites were investigated. As the intercalation time was prolonged, the surface of MoS2 exhibited a totally crumpled structure and more functional groups formed. Because of the higher functional group concentration, the interfacial adhesion force between EP and MoS2 was enhanced. With the addition of 1.0 wt% exfoliated MoS2 fillers, the tensile strength and tensile modulus of EP were even improved ~500% and ~6800%, respectively. Therefore, this work provides a facile way to produce high-performance EP nanocomposites.     

Polymer Nanocomposites in Sensor Applications: A Review on Present Trends and Future Scope

Polymers are crucial constituents of modern electronic devices. They can be used in their pristine, composite or nanocomposite forms for several domestic and industrial applications with innumerable unique possibilities. Polymer nanocomposites have gained wide theoretical interest and numerous practical applications in diverse fields of science and technology as they bestow the materials not only with virtuous processability but also with exceptional functionalities. It is evidenced that the electrical conductance of polymer nanocomposite is governed by the conductive filler networks within the polymer matrix. Hence, insignificant variation in the conductive networks can result in noteworthy variations in the output electric signal of polymer nanocomposite. Exploiting this stimuli-responsive performance of conductive networks to the physical parameters, polymer nanocomposites can be harnessed to fabricate novel sensitive sensors to detect vital physical parameters viz.strain/stress, pressure, temperature, solvent or vapor. Technical and phenomenological studies on polymer nanocomposites are still enduring.Advanced explanations are being sought but the mechanisms governing the formation of several polymer nanocomposites are still topics of debate in the material science community. Their in-depth investigation requires copious scientific work. This review analytically sketches the synthesis, microstructures, physiochemical properties and the underlying mechanisms for stimuli-responsiveness to the physical parameters of the polymer nanocomposites as well as their applications in various sensitive sensors and detectors. Thus, it became evocative for this review to focus on their processing methodologies, physiochemical physiognomies, classification and probable potentials of polymer nanocomposites.This review primarily presents the current literature survey on polymer composites and the gap areas in the study encourages the objective of the present review article. Finally, the status, perspectives and the advantages of specific polymer nanocomposites at present are summarized. The attention of this review is drawn to the present trends, challenges and future scope in this field of study. Finally, the vital concern and future challenge in utilizing the stimulus responsive behavior of polymer nanocomposites to design versatile sensors for real time applications are elaborately discussed.