有机/无机纳米复合粒子平衡型态的热力学计算

有机/无机纳米复合粒子是一种应用广泛的复合材料, 采用细乳液聚合方法是制备此类复合粒子的有效途径, 其中分裂/融合过程是一种新型的制备工艺. 纳米复合粒子的型态控制是一个非常重要的方面, 从热力学角度出发, 把界面Gibbs自由能最低这一基本热力学原理应用于计算细乳液聚合、采用新型分裂/融合工艺制备的有机/无机纳米复合粒子平衡型态, 并推导了核壳型、半球型、夹心型和分离型复合粒子平衡型态的热力学方程. 通过比较特定制备条件下不同形态复合粒子的界面Gibbs自由能, 可以预测最稳定的有机/无机纳米复合粒子平衡型态.     

树莓状粒子的制备及应用研究进展

树莓状粒子是指具有较大比表面积、表面粗糙度和较高光散射特性的形似树莓的微粒。因其具有特殊的表面形态且表面易于设计,在颗粒自组装、超疏水和超亲水涂层制备方面有广泛的应用。树莓状结构粒子从物质组成上主要分为无机/有机、无机/无机和有机/有机复合粒子三种类型。迄今已有多种制备树莓状复合粒子的方法,但由于其组分的千变万化,还没有一种通用的方法。本文总结了近几年树莓状粒子的制备方法及其应用研究进展。     

细乳液聚合法制备有机/无机纳米复合材料

无机纳米粒子的引入可以使聚合物材料获得抗菌、导电和防紫外等诸多特性,但无机纳米粒子在聚合物基质中易团聚、引入量少,难以充分发挥其优点。细乳液聚合法基于其独特的成核方式--液滴成核,能够提高无机纳米粒子在聚合物基中的分散性和引入量,且复合材料的形貌易于控制,是目前制备特殊形貌有机/无机纳米复合材料的一种有效手段。本文介绍了有机/无机复合纳米材料的细乳液制备过程,综述了近年来不同无机纳米粒子与有机基质复合的研究进展,例如：纳米SiO₂、纳米ZnO、金属纳米粒子、纳米氧化石墨烯等。最后就其发展现状提出了几点建议。     

单分散SiO2/PS复合粒子的制备

聚合物包覆无机物的核一壳结构复合粒子研究长期以来受到关注,源于其应用广泛．根据表面性质要求对无机相或者有机相表面进行功能化,可使得到的复合粒子与不同的应用体系相匹配．这类聚合物包覆无机物的有机／无机复合粒子,已在光学器件、分离、药品、农业、涂料等很多领域有广泛和潜在应用．本文制备这类复合粒子用于石油工业模型催化剂和助剂．     

表面引发原子转移自由基聚合法合成无机/有机核壳复合纳米粒子

原子转移自由基聚合(ATRP)是目前为止最具工业化应用前景的活性/可控自由基聚合方法之一,其最大特点是可以得到分子量分布窄、链结构规整的聚合物,而且可聚合的单体种类多,反应条件温和并易控制。表面引发ATRP(SI-ATRP)特别适合于无机材料表面接枝聚合物或无机/有机复合材料的制备,近年来引起了国内外研究者的高度关注。本文首先对SI-ATRP的反应过程与特点做了阐述,然后重点述评了用SI-ATRP法合成以非金属氧化物纳米粒子、金属氧化物纳米粒子、金属纳米粒子或其他无机纳米粒子为核的无机/有机复合纳米粒子的研究进展,最后对未来用SI-ATRP法合成无机/有机复合纳米粒子的发展方向和研究前景进行展望。     

有机-无机纳米复合微球研究进展北大核心CSCD

有机-无机纳米复合微球是指两种或两种以上的粒子经表面包覆或复合处理后形成的纳米尺度颗粒。近年来,有机-无机纳米复合微球在各领域具有广泛应用前景而备受关注。本文归纳了目前比较成熟的合成技术和先进工艺,将制备有机-无机纳米复合微球的方法分为溶胶-凝胶法、原位聚合法及其他实验方法,详细介绍了原位聚合法,分别从各类方法的特点和应用等方面进行详尽地分析和阐述,并对有机-无机纳米复合微球的实际应用做了比较系统的总结。最后,展望了有机-无机纳米复合微球的发展和前景。     

模板法合成核壳功能材料

模板法制备核壳功能材料是材料科学研究领域的一大热点引起了广泛的关注.本文结合本课题组在有机-无机核壳复合纳米粒子(空心球)领域的研究,较系统地评述了目前国内外利用模板法制备核壳粒子的研究进展,并概述了核壳纳米粒子(空心球)的发展前景和应用领域.     

无机-高分子磁性复合粒子的制备与表征

详细地研究了乳化剂用量对种子乳液聚合反应的影响,并成功地制备出粒径约300nm的苯乙烯/丙烯酸共聚小球。另外,还报道使用化学共沉淀法使无机粒子与高分子球复合,制备出高分子球为核,无机粒子为壳层的磁性复合粒子,使用XRD、TEM等手段对此复合粒子进行了表征。同时,进一步研究了这种复合粒子悬浮液的悬浮性能以及粘度随磁场的变化情况。     

Pickering乳滴模板法制备超粒子结构有机/无机杂化微球

Pickering乳滴模板法制备有机/无机杂化的核壳微球越来越引起人们的关注,主要因为该方法制备出的微球具有以无机粒子为壳层的超粒子结构(supracolloidal structure),能够赋予微球独特的功能.胶体粒子在乳滴表面自组装形成有序的球面胶体壳,得到稳定Pickering乳液,固定乳滴表面的胶体粒子来制备核壳结构的微球或者以胶体粒子为壳层的微胶囊(colloidosome).本文综述了我们课题组以Pickering乳滴模板法制备超粒子结构有机/无机杂化微胶囊包括实心微球方面的工作.我们选择具有不同性能、种类的胶体粒子以及具有不同性质和功能的核材料,采用Pickering乳滴模板法,对吸附在乳滴表面的胶体粒子用不同的固定方法制备具有不同结构和性能的微球和微胶囊,利用基于多重Pickering乳液的聚合技术制备双纳米复合的超粒子结构多核聚合物微球.     

聚苯硫醚/低熔点玻璃复合体系的熔融制备与力学性能

选取低熔点玻璃(LMTG)为无机组分,聚苯硫醚(PPS)为聚合物基体,在适宜的温度下熔融制备了复合体系(PPS/LMTG).探讨了加工工艺对体系中LMTG无机相形态的影响,研究了加工温度低于LMTG软化温度制备的普通填充体系(PPS/LMTG300)和高于软化温度制备的熔融液-液复合体系(PPS/LMTG400)的力学性能.结果表明,对于所选择的体系,可以在325~450℃内实现有机无机相液-液复合;温度场、剪切场均影响LMTG分散相的形貌,液-液复合过程中LMTG分散相液滴在剪切场中呈现类似变形、破裂、凝聚和松弛回复等特征;与普通填充体系PPS/LMTG300相比,由液-液复合得到的PPS/LMTG400体系中无机相在复合过程中原位生成平均粒径更小的形态,其粒子基体相互作用减弱;且经过液-液复合,粒子分散性得到了较大的改善,PPS/LMTG400体系中即使含量高达66 wt%,无机粒子仍然具有优良的增强效果.     

Synthesis of PVAc/SiO2 latices stabilized by silica nanoparticles

This paper presents a method for the preparation of raspberry-like organic-inorganic composite spheres with poly(vinyl acetate) (PVAc) as core and nanosilica particles as shell. A small amount of anionic reactive surfactant, 3-allyloxy-2-hydroxy-1-propanesulfonic acid sodium salt (HAPS), was used as co-stabilizer and nanosilica particles were adsorbed onto the growing latex core in aqueous medium via the formation of hydrogen bonds between nanosilica particles and PVAc particles. TEM indicated that the hydrogen bonds between nanosilica particles and PVAc were strong enough for the formation of long-stable composite spheres with raspberry-like morphology. Influences of some synthetic parameters, for instance, type of silica sol, initial silica amount, and different kinds of low-molecular-weight surfactant, on the morphology of the composite spheres and properties of the latex films were studied in detail. A possible formation mechanism of the composite spheres was also proposed.     

有机-无机复合质子交换膜的制备与界面特性

有机-无机复合质子交换膜的开发是燃料电池用质子交换膜的一个重要研究方向,本文综述了有机-无机复合质子交换膜的制备方法,分析了两相之间的界面特性,并对这种复合膜的研究前景进行了展望.     

有机-无机复合气凝胶研究进展

气凝胶具有低密度、低热导率、高比表面积及高孔隙率等优异性能,在隔热、传感、催化、吸附、储能等领域显示出良好的应用前景。但气凝胶的多孔网络结构也造成了其强度低和韧性差等问题,严重制约了气凝胶的实际应用,有机-无机复合是一种增强气凝胶力学性能的有效方法。而且,采用有机-无机复合方法制备气凝胶还可以赋予气凝胶阻燃等其他新颖的性能。本文综述了有机-无机复合气凝胶的新研究进展,分析其原理、合成方法及相关性能,指出了有机无机复合气凝胶的优势和存在问题并展望了未来的发展方向。     

Preparation of poly(acrylamide)/nanoclay organic-inorganic hybrid nanoparticles with average size of ∼250 nm via inverse Pickering emulsion polymerization

In this study, the preparation of poly(acrylamide)/nanoclay organic-inorganic hybrid nanoparticles via surfactant-free inverse emulsion polymerization by using organically modified clay platelets as stabilizers was discussed. Colloidally stable inverse Pickering emulsions of aqueous acrylamide solution in cyclohexane (solvent) stabilized by hydrophobic Cloisite 20A (MMT20) were prepared. Polymerization was carried out via 2,2′-azobis(isobutyronitrile) and composite particles with an average size of ～250 nm were obtained. The effect of initiator and solvent type on the stability, size, size distribution, and morphology of the produced composite particles was examined. It was observed that in the presence of xylene as solvent, particles with bigger sizes and broader size distribution were obtained. Furthermore, using an ionic initiator resulted in a slight coagulation during polymerization and smaller particles. Moreover, the effect of various polymerization conditions such as temperature, initiator, and crosslinking agent concentration and clay content on the polymerization rate was evaluated. The experimental results showed that polymerization rate increases with an increase in polymerization temperature, crosslinking agent concentration, and initiator content. However, increasing in clay content results in a lower polymerization rate.     

酞菁钴/纳米铁复合颗粒的结构与微波电磁特性

一些铁磁性金属及其合金超细粉末,具有比饱和磁化强度高、易于合成与粒径可控等优点,因此被广泛应用于磁流体、电磁流变液、微波吸收材料等领域,但由抗氧化性差、密度较大等主要缺点而使其应用受到限制,采用有机／无机复合技术可制备具有有机包覆层的有机／无机复合颗粒,不仅可以增强铁磁性颗粒的抗氧化性,减小了密度,而且可以提高与有机基体的亲和性,为该类材料向更高层次发展提供了可能。     

非离子乳化剂细乳液聚合制备草莓型PSt/SiO2纳米复合微球

通过细乳液聚合,使用非离子乳化体系辛基酚聚氧乙烯醚(CA-897),在纳米二氧化硅水分散介质中,以1-乙烯基咪唑(1-VID)作为辅助单体制备了苯乙烯为核,纳米二氧化硅为壳的草莓型PSt/SiO2有机-无机复合微球.实验范围内得到的复合微球的平均粒径和最终SiO2含量分别介于140～180 nm和19 wt%-31wt...     

Morphology stability of lamellar composite magnetic materials

The aim of this study was to investigate the role of the copolymers and nanoparticles during elaboration of new stable composite materials. We have shown that the interactions between the mesophases that form the copolymers and nanoscopic particles can lead to highly organized hybrid materials. The morphology of such composites depends on the characteristics of both copolymers and nanoparticles. On one hand, diblock copolymers must form a strong segregation limit and have a higher mass. On the other hand, nanoparticles must show strong affinity for one of the two polymeric species of the copolymer and be as small as possible. In this case, a composite organic-inorganic material can be obtained with a periodic distribution of the particles in the polymeric matrix. This study can be applied to other copolymer-nanoparticle mixtures and used to design advanced composite architectures.     

Electrochemical Behavior and Its Electrocatalytic Activity of A P—Mo Heteropolyanion Modified ITO Electrode

ITO is a versatile material in the electronic industry because of its special transparent and conductive properties. However, there are a few reports regarding the adsorption of organic or organometallic compounds on the ITO surface1-4. The heteropolyanions are interested in the field of material science, catalytics, biology, and medicine owing to their chemical, structural, and electronic versatility5-7. One of the most important properties of polyoxometalate anions is their ability to a…     

Organic nanocrystals grown in sol-gel matrices: new hybrid organic-inorganic materials for optics

We have developed a simple and generic preparation of stable organic nanocry stals grown in gel-glass matrices. The synthesis of these hybrid organic-inorganic materials is based on the confined nucleation and growth of organic phases in the pores of dense gels. For bulk nanocomposite samples, narrow size distributions of particles (10–20 nm in diameter) are obtained. We have extended this method to the preparation of organic nanocrystals embedded in sol-gel thin films prepared by spin-coating. For all these nanocomposite materials, we have significantly increased the dye stability and obtained promising optical properties: luminescence, non-linear optical properties or photochromism. Moreover, we have also demonstrated basic working principles of a new type of fluorescent nanosensor through the preparation of organic luminescent nanocrystals grown in silicate films.     

The absence of size-dependency in flame retarded composites containing low-melting organic-inorganic glass and clay: Comparison between micro- and nanocomposites

Due to optimised processing of epoxy based composite materials containing a low-melting organic-inorganic glass together with an organo clay, the size of the glass particles could be successfully reduced. Thus truly nano-dispersed composites were obtained, with glass particles in the range of 10 nm to 200 nm. The small particle size allowed efficient interaction of glass particles and organo clay layers. The flame retardancy as well as the thermo-mechanical properties were tested, and the results showed that the low-melting glass led to a remarkable reduction of peak heat release rate by forming an enhanced barrier layer. Nevertheless no further improvement could be achieved by lowering the particle size to the nanometre region. For good flame retardancy a microdispersion of the low-melting glass was already sufficient.