中空微球及其制备方法

中空微球具有低密度、高比表面积且可以容纳客体分子等特点,在众多领域受到广泛关注.本文对聚合物中空微球、无机中空微球、聚合物/无机复合中空微球的制备方法进行了综述,并介绍了一种在使用过程中形成中空结构的可膨胀微球.     

含C60聚苯乙烯微球的制备及光电导性能研究

目前,多功能、高性能聚合物微球的合成及应用已成为研究热点.制备聚合物微球的方法有乳液聚合法、分散聚合法、无皂乳液聚合法、超微乳液聚合法和悬浮聚合法等.制备微米级微球通常采用乳液聚合法和分散聚合法.     

刺激响应性聚合物微球的制备、性能及应用

作为典型的软物质材料,聚合物微球因其独特的微尺度、扩散性、渗透性及可修饰性而广泛应用于催化、药物传输、生物传感、微反应器、化学分离以及涂层材料等领域。为满足苛刻应用环境对微球的性能要求,相继出现了各类环境响应性聚合物微球。针对近年来刺激响应性微球的研究进展,本文综述了聚合物响应性微球的制备策略及形貌,以及对温度、pH、磁场、离子强度、光和CO₂敏感的响应性聚合物微球体系;并讨论了不同类型刺激响应微球的响应机理及应用,分析了其存在的不足,展望了其应用前景和发展方向。     

聚合物中空微球的制备及碱后处理因素的正交试验研究

首先采用种子乳液聚合法合成高羧基含量的核壳聚合物微球,然后利用碱液进行后处理,经渗透溶胀后可形成具有中空结构的聚合物微球,考察了单体加料工艺和聚合配方对聚合稳定性及微球形貌的影响,通过正交试验设计研究了不同的碱后处理条件对溶胀后微球形貌的影响程度,并进行了极差和方差分析.结果表明,控制单体加料速度和引入中间极性过渡层,有利于核壳聚合物微球的制备;碱液用量为影响溶胀后聚合物微球形貌的主要因素,碱处理温度次之,碱处理时间的影响相对较弱.当碱酸摩尔比为1~1.15,碱处理温度为80~90℃,碱处理时间为1~5 h时,制得的聚合物微球具有良好的中空结构.     

基于聚合物的轻质微球的制备和应用

具有密度低、比表面积高、稳定性好、表面渗透能力强和负载能力高等特点的轻质微球得到了国内外研究者的关注。本文综述了基于聚合物轻质微球的最新研究进展,详细介绍了中空微球和多孔微球的制备方法,主要包括种子溶胀法、模板法、悬浮聚合法、层层自组装法、表面分子印迹法和液-液相分离法,阐述了轻质微球在生化医学、涂料、废水处理、生物传感器及电子信息领域等方面的应用进展,指出了有效控制中空微球内腔结构,调控多孔微球的孔结构是未来的研究方向。     

磁性核壳介孔氧化硅微球的制备与应用

磁性核壳介孔氧化硅微球作为一种新型功能复合材料,已成为众多研究领域的一个研究热点。本文综述了近年来利用模板法合成磁性核壳介孔氧化硅微球的研究进展,重点阐述了溶胶-凝胶法和微乳液法在实心微球和中空微球制备中的应用。介绍了磁性介孔二氧化硅微球在蛋白质、DNA分离,靶向药物传输等生物医学上的应用以及磁性酸催化、加氢催化、纳米贵金属催化、光催化等催化领域的应用,并对其未来的发展趋势做了展望。     

《化学通报》网络版(Chemistry Online)2005年第2期论文摘要

[w0 1 3 ]乳液法制备中空聚合物微球PreparationofHollowPolymerParticlesbyEmulsionPolymerization白飞燕　方仕江 (浙江大学化学工程与生物工程学系化学工程联合国家重点实验室聚合反应工程实验室　杭州　 3 1 0 0 2 7)　　介绍了最近国内外有关乳液法技术 ,包括SPG(ShirasuPorousGlass)膜乳化聚合法、W O W乳液聚合法和封装非溶剂乳液聚合法制备中空聚合物微球的研究进展 ,着重分析了上述几种方法的成孔机理及其优缺点 ,并简单介绍了中空聚合物微球的应用领域。　　Theprogressinthepreparationofhollowpolymerparticlesbyvariou…     

聚合物空心微球的研究进展

聚合物空心微球由于其独特的性质及其广阔的应用,近年来受到越来越多的关注.本文综述了近年来制备聚合物空心微球的方法,如:自组装法、模板法、微乳液法等.并简要介绍了聚合物空心微球在医学材料等方面的应用.     

聚合物微纳米管的制备技术

由于聚合物微纳米管独特的一维中空结构和性能多样性,在分离、电子器件、催化剂负载、药物释放等方面具有广泛的应用前景,本文结合最新的研究进展,总结了聚合物微纳米管的制备方法,并重点介绍了硬模板法、软模板法和无模板法的特点。     

模板法制备聚苯乙烯/聚4-乙烯基吡啶功能微球

以工业化的聚苯乙烯中空微球为模板,利用种子乳液法合成了粒径均一的功能化中空聚苯乙烯/聚4-乙烯基吡啶(PS/P4VP)微球,改变制备条件可以控制功能基团4-乙烯基吡啶(4-VP)在聚苯乙烯微球表面的分布.合成的微球在水和有机溶剂如二氯甲烷、乙醇、乙腈等中有良好的分散性,并能促进油水体系混溶.     

中空全固态Z型异质结光催化剂的研究进展

中空结构材料由于比表面积大、密度低和电荷传输距离短等特点,在光催化反应中具有巨大的应用价值. Z型光催化剂具有宽光谱响应、高稳定性、高光生载流子的分离效率以及强氧化还原能力等优点,受到了广泛关注.然而,由于Z型多元组分和中空结构不稳定,设计并制备高效稳定的中空全固态Z型光催化剂仍是一大挑战.本文综合评述了近年来中空全固态Z型光催化剂的种类、构筑策略及性能等方面的研究进展,并进一步展望了其在未来应用中面临的问题与挑战,最后归纳总结了其设计与发展方向,为高效稳定光催化剂的设计提供了思路.     

Hollow latex particles: synthesis and applications

One of the major developments in emulsion polymerization over the last two decades has been the ability to make hollow latex particles. This has contributed many fundamental insights into the synthesis and the development of structure in particles. Hollow latex particles also enhance the performance of industrial coatings and potentially are useful in other technologies such as microencapsulation and controlled release. Ever since the publication of the initial process patents describing these particles, there has been a global R&D effort to extend the synthetic techniques and applications. One prominent synthetic approach to hollow particles is based on osmotic swelling. This dominates the literature, and usually starts with the synthesis of a structured latex particle containing an ionizable core that is subsequently expanded with the addition of base. Fundamental to this approach are a sophisticated control of transport phenomena, chemical reactivity within the particle, and the thermoplastic properties of the polymer shell. Hydrocarbon encapsulation technology has also been employed to make hollow latex particles. One approach involves a dispersed ternary system that balances transport, conversion kinetics, and phase separation variables to achieve the hollow morphology. Other techniques, including the use of blowing agents, are also present in the literature. The broad range of approaches that affords particles with a hollow structure demonstrates the unique flexibility of the emulsion polymerization process.     

Synthesis and utilization of monodisperse hollow polymeric particles in photonic crystals

We developed a process to fabricate 150-700 nm monodisperse polymer particles with 100-500 nm hollow cores. These hollow particles were fabricated via dispersion polymerization to synthesize a polymer shell around monodisperse SiO(2) particles. The SiO(2) cores were then removed by HF etching to produce monodisperse hollow polymeric particle shells. The hollow core size and the polymer shell thickness, can be easily varied over significant size ranges. These hollow polymeric particles are sufficiently monodisperse that upon centrifugation from ethanol they form well-ordered close-packed colloidal crystals that diffract light. After the surfaces are functionalized with sulfonates, these particles self-assemble into crystalline colloidal arrays in deionized water. This synthetic method can also be used to create monodisperse particles with complex and unusual morphologies. For example, we synthesized hollow particles containing two concentric-independent, spherical polymer shells, and hollow silica particles which contain a central spherical silica core. In addition, these hollow spheres can be used as template microreactors. For example, we were able to fabricate monodisperse polymer spheres containing high concentrations of magnetic nanospheres formed by direct precipitation within the hollow cores.     

微流体技术制备聚合物微粒的研究进展 Ⅰ.合成聚合物颗粒的方法及颗粒种类

综述了微流体技术合成聚合物颗粒的研究进展,包括基于液滴的合成、用流动刻蚀的技术合成及在设备中交替组装成复杂颗粒等合成组装技术,介绍了由此合成的一些不同形状和结构的颗粒及其性能,其中包括具备低密度和特殊表面性能的多孔性颗粒、可以通过加入功能物质制备出的性能优异的复合颗粒、拥有层状结构及多重性能的多功能颗粒、基础的球形颗粒以及通过微流体设备制备的非球形颗粒。     

Submicron Sized Hollow Polymer Particles: Preparation and Properties

The considered method for obtaining hollow polymer particles is based on the following pathway: (1) preparation of a carboxylated core latex by emulsion copolymerization of acrylic monomers with methacrylic acid, (2) synthesis of a core-shell latex comprising a styrene (co)polymer shell, (3) neutralization of the core carboxylic groups with a base followed by the core ionization and hydration to a high degree, shell expansion and formation of water-filled hollows. A number of approaches to improve the hydrophilic core – hydrophobic shell compatibility and enlarge the hollow volume are considered. The synthesized hollow particles are of a submicron size with the relative hollow volume V_hol : V_part.= 0.43 – 0.64. Methods for cationic hollow particle latex preparation by anionic latex recharging with a cationic surfactant or acidic melamine resin are discussed. Recharging with a melamine resin is shown to afford hollow particles with an external polymer shell providing a high thermal stability of the particles.     

Magnetic hollow poly(N-isopropylacrylamide-co-N,N′-methylenebisacrylamide-co-glycidyl acrylate) particles prepared by inverse emulsion polymerization

To prepare functionalized magnetic polymer particles that are thermally responsive, inverse emulsion copolymerization of N-isopropylacrylamide, N,N′-methylenebisacrylamide and glycidyl acrylate (GA) was investigated in paraffin oil in the presence of γ-Fe₂O₃ nanoparticles dispersed in a water/glycerol mixture. The resulting polymer particles were characterized regarding the morphology, size, polydispersity, iron content, and the temperature-dependent phase transition using optical microscopy, transmission electron microscopy, scanning electron microscopy, atomic absorption spectroscopy, and differential scanning calorimetry. Magnetic properties were examined using hysteresis loop measurements and by analyzing the magnetic susceptibility with respect to temperature. We have also investigated the influence of the concentration of γ-Fe₂O₃ and GA in monomers on properties of the particles (morphology, size, and presence of oxirane groups). The particles possessed a hollow structure as a result of phase separation between water/glycerol hydrophilic solvents in the polymerization feed and the forming polymer. Depending on the concentration of γ-Fe₂O₃ in the monomer phase, the magnetic hollow particles contained 5–24 wt% iron. In water, the particles gradually collapsed when the temperature was raised to 40 °C because the elevated temperature weakened hydration and the PNIPAAm chains gradually became more hydrophobic.     

Facile fabrication of monodisperse polymer hollow spheres

This article reports the facile synthesis of monodisperse polymer hollow spheres by seeded emulsion polymerization without additional treatment. In this method, P(St-MMA-MAA) copolymer latex particles were first prepared by emulsifier-free emulsion polymerization and then used as seeds to carry out emulsion polymerization of methyl methacrylate (MMA), divinyl benzene (DVB), and 2-hydroxyethyl methacrylate (HEMA) with potassium persulfate (KPS) as initiator at 80 degrees C. The void of hollow spheres was readily adjusted by changing the monomer/seed weight ratio, and it could be enlarged while the diameters of hollow spheres changed little after etching by dimethyl formamide (DMF). The effects of synthetic parameters including the monomer composition and the properties of seeds on the morphology of hollow spheres were investigated in detail. On the basis of the experimental results, it seemed reasonable to conclude that the formation of hollow spheres was due to the "dissolution" of seeds in monomers and phase separation between the constituent polymers. As a thermodynamic factor, sodium dodecyl sulfate (SDS) would allow the preparation of solid particles depending on its level.     

复杂中空结构材料的构筑及能源应用

随着能源问题的日益突显,开发新型多功能材料以满足能源存储与转换应用的需求变得尤为重要.在众多功能材料中,复杂中空结构材料由于其独特的结构和物理化学特性而备受关注.本文综合评述了复杂中空结构材料的普适性构筑方法(硬模板法、软模板法、自模板法、次序模板法和选择性刻蚀法)及在能源方面的应用(锂/钠/钾离子电池、锂硫电池、超级电容器、电催化、光催化及染料敏化电池等).最后,对复杂空心结构研究领域存在的问题及未来的发展方向进行了展望.     

聚全氟乙丙烯中空纤维膜研究

以聚全氟乙丙烯(FEP)为成膜聚合物,复合无机粒子为成孔剂,邻苯二甲酸二辛酯(DOP)为稀释剂,采用熔融纺丝工艺制备得到FEP中空纤维膜.分析和讨论了不同成膜体系对FEP中空纤维膜热性能、动态力学性能和力学性能的影响,并对膜的纯水通量和孔径分布进行表征.用扫描电子显微镜(SEM)观察了膜的横断面和表面形貌.结果表明,所得FEP中空纤维膜为由溶出微孔和界面微孔组成的海绵状孔结构.随着成孔剂含量的增加,成孔剂在成膜体系中分散程度变差,容易发生团聚,最终导致膜孔径变大,孔径分布变宽.成孔剂和稀释剂对FEP中空纤维膜的热性能和动态力学性能影响较小.当FEP含量增加到70 wt％时,膜表面容易形成一层致密层,降低了膜的通透性.     

Polymerization of electric field-centered double emulsion droplets to create polyacrylate shells

Porous and hollow particles are widely used in pharmaceuticals, as solid phases for chromatography, as catalyst supports, in bioanalytical assays and medical diagnostics, and in many other applications. By controlling size, shape, and chemistry, it is possible to tune the physical and chemical properties of the particles. In some applications of millimeter-scale hollow shells, such as in high energy density physics, controlling the shell thickness uniformity (concentricity) and roundness (sphericity) becomes particularly important. In this work, we demonstrate the feasibility of using electric field-driven droplet centering to form highly spherical and concentric polymerizable double emulsion (DE) droplets that can be subsequently photopolymerized into polymer shells. Specifically, when placed under the influence of an ～6 × 10(4) V(rms)/m field at 20 MHz, DE droplets, consisting of silicone oil as the inner droplet and tripropylene glycol diacrylate with a photoinitiator in N,N-dimethylacetamide as the outer droplet, suspended in ambient silicone oil, were found to undergo electric field-driven centering into droplets with ≥98% sphericity and ～98% concentricity. The centered DE droplets were photopolymerized in the presence of the electric field. The high degrees of sphericity and concentricity were maintained in the polymerized particles. The poly(propylene glycol diacrylate) capsules are just within the sphericity requirements needed for inertial confinement fusion experiments. They were slightly outside the concentricity requirement. These results suggest that electric field-driven centering and polymerization of double emulsions could be very useful for synthesizing hollow polymer particles for applications in high energy density physics experiments and other applications of concentric polymer shells.