磺化聚苯乙烯胶体晶的红外光谱分析

单分散乳胶体系可以通过自组装形成有序的胶体晶结构,在窄波段光过滤器[1]、生物医学传感器[2]、智能化学传感器[3] 等领域具有重要的应用价值.最近,人们以此有序结构作为模板,制备了有序孔材料[4～7] .另外,此有序结构在仿生学如模拟蛋白石等有序结构等方面也具有重要意义[8].但是,一般的单分散体系如聚苯乙烯体系所形成的有序结构都属于硬性材料,缺乏对外场的响应特性.此外,微球表面没有功能性基团,很难与其它物质兼容,这使得其作为模板合成其它复合材料的潜力大大降低. ANALYSIS OF FT-IR SPECTRA OF THE SULFONATED POLYSTYRENE COLLOIDAL CRYSTALS     

磺化聚苯乙烯胶体晶的红外光谱分析

单分散乳胶体系可以通过自组装形成有序的胶体晶结构 ,在窄波段光过滤器[1] 、生物医学传感器[2 ] 、智能化学传感器[3] 等领域具有重要的应用价值 .最近 ,人们以此有序结构作为模板 ,制备了有序孔材料[4～ 7] .另外 ,此有序结构在仿生学如模拟蛋白石等有序结构等方面也具有重要意义[8] .但是 ,一般的单分散体系如聚苯乙烯体系所形成的有序结构都属于硬性材料 ,缺乏对外场的响应特性 .此外 ,微球表面没有功能性基团 ,很难与其它物质兼容 ,这使得其作为模板合成其它复合材料的潜力大大降低 .本实验室通过对聚合物胶体晶进行改性 ,使其成为功…     

胶体晶体中的两种排列方式及堆积模式

由单分散的有机或无机粒子制备三维有序的胶体晶体越来越受到人们的关注 [1～ 3 ] ,单分散颗粒如何排布和堆积是形成三维有序胶体晶体的关键 .自然界中的蛋白石 (Opal)是由单分散 Si O2 粒子的三维有序堆积中渗入水溶性的硅酸盐固化而成的 .仿照自然界的模式由单分散的有机或无机粒子制备三维有序的胶体晶体是对当今科学技术的一个挑战 [4 ] .以胶体晶体为模板制备有机、无机、金属和陶瓷等的多孔材料在催化、吸附以及光子晶体等方面具有重要的应用前景 [5～ 9] .本文研究了以单分散的聚苯乙烯 -甲基丙烯酸甲酯 -丙烯酸 [P(St- MMA- AA)…     

聚苯乙烯光子晶体的制备及其在传感中的应用

以基于毛细作用的垂直沉积法将单分散的二氧化硅胶体微球自组装成光子晶体．在二氧化硅光子晶体的多孔结构里填充聚苯乙烯甲苯溶液，经甲苯挥发，通过氢氟酸处理去除二氧化硅模板，制备出精美的聚苯乙烯光子晶体．研究表明：保留了模板有序多孔结构的聚苯乙烯能被用来作为敏感膜，这使得其在基于折射率变化的传感应用中具有潜在的价值．     

乙烯基化的中空二氧化硅球的制备与表征

在乙醇/氨水介质中,以分散法制备的聚苯乙烯微球为模板,通过乙烯基三乙氧基硅烷水解缩合反应在聚苯乙烯表面形成包覆层.然后将聚苯乙烯球核溶解而制备了乙烯基化二氧化硅空心微球.     

反蛋白石光子晶体凝胶的pH响应

首先采用Stber方法制备了一系列亚微米级单分散二氧化硅小球,而后通过垂直沉降自组装方法制备了颜色鲜艳的二氧化硅三维有序结构胶体晶体模板,最后再采用模板聚合法在220 nm二氧化硅小球自组装的阵列间隙中共聚甲基丙烯酸和乙二醇二甲基丙烯酸酯,经氢氟酸刻蚀二氧化硅模板后得到多孔有序的反蛋白石光子晶体.当pH值从5升至8时,反蛋白石凝胶光子晶体的反射峰波长从514 nm移动至590 nm,颜色变化显著,从蓝绿色变成红色,突变点为pH=6.5,而且pH响应在100 s左右即可达到平衡.对交联剂用量的研究结果表明,随着交联剂乙二醇二甲基丙烯酸酯用量从4%增加到16%,光子晶体响应pH时的红移量减小.     

壳层可控导电聚吡咯/聚苯乙烯复合微球及聚吡咯中空微胶囊的制备

在导电聚合物含量较小时,含核壳结构的导电聚合物复合粒子就可以具有和本体相当的导电率,且加工性好,近年来这种核壳结构微粒的制备已引起了科学家们的广泛关注．Armes等[制备了导电聚吡咯、导电聚苯胺包覆聚苯乙烯的核壳结构胶体粒子及聚苯胺和二氧化硅的纳米复合物．刘正平等用改进的方法在粒径为116nm的单分散聚苯乙烯乳胶粒子上包覆聚吡咯,     

二氧化硅胶体晶模板技术制备间规聚苯乙烯有序孔材料

结晶高分子在受限空间中的聚合行为及聚集态均与本体的有着显著的差异 ,因而呈现不同的性能[1] .受限空间是指介观有序的分子筛 .间规聚苯乙烯具有熔点高、结晶速度快、弹性模量高、绝缘及抗溶剂性能优良等特点 ,具有广阔的应用前景 .自从 Ishihara等 [2～ 5]首次报道苯乙烯间规聚合以来 ,国内外对间规聚苯乙烯的均聚和共聚反应进行了大量研究 .苯乙烯在二氧化硅胶体晶中通过自由基聚合得到三维有序聚苯乙烯孔材料 ,实验表明 ,即使在亚微米的受限空间内 ,聚苯乙烯的生成和性质也会发生明显变化 [6] .本文以有序二氧化硅胶体晶为模板 ,在其…     

聚苯乙烯光子晶体高效制备

以苯乙烯单体为原料,采用一步聚合自组装法制备了具有蛋白石结构的聚苯乙烯(PS)光子晶体(1);以1为模板制备了反蛋白石结构的TiO2光子晶体(2)来验证1的有序性;探讨了1的制备机理。1和2的结构和形貌经IR,SEM和TEM表征。讨论了乳化剂SDS的用量对PS微球排列有序性的影响。结果表明,SDS用量在30 mg～74 mg时,PS微球的粒径不断减小,微球排列的有序性受到影响;当SDS用量为52 mg时,PS微球排列的有序性最佳,能够形成蛋白石结构的1;2在大范围内有序排列进一步证明了1的高度有序性。     

二元共组装法制备无裂痕反蛋白石结构薄膜的研究

近年来,由于在光学、电学和生化等领域具有广泛的潜在应用,有序多孔反蛋白石结构薄膜的研究引起了人们的广泛关注.但是其在制备过程中常常会形成一些无法控制的缺陷,限制了这类材料的普及和实际应用.通过使用两种基质前驱体（正硅酸乙酯或丝素蛋白）与胶体小球混合共组装,探究了二元体系共组装法制备无裂痕反蛋白石结构薄膜的可行性.并用扫描电镜和可见光谱对薄膜结构进行了表征.结果表明,对于正硅酸乙酯体系,在不影响胶体小球有序排列的条件下,正硅酸乙酯在小球间的空隙中发生溶胶凝胶转变,与微球共同组装成有序致密的整体,去除微球模板后,可以得到大规模（>200 μm）无缺陷有序的反蛋白石结构薄膜.而对于大分子丝素蛋白体系,由于它和胶体小球有较强的相互作用力,会抑制胶体小球的有序组装,导致无法形成有序结构薄膜.对两种二元共组装体系进行了实验探索,实验结果不仅有助于人们了解共组装方式的适用范围,而且为设计和制备无缺陷反蛋白石薄膜提供了新的途径.     

Novel and facile method for the preparation of monodispersed titania hollow spheres

The fabrication of monodispersed hollow spheres in varying sizes and shapes is very interesting and has a lot of potential applications. This paper provides a very simple route to preparing hollow titania spheres using polystyrene (PS) as a template. In this approach, the titania shells were first formed and the PS cores were dissolved subsequently, even synchronously, in the same medium; neither an additional dissolution nor a calcination process was needed to remove the PS cores. Transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and Barret-Emmet-Teller measurements were used to characterize the monodispersed hollow titania spheres. A possible formation mechanism of the hollow spheres was proposed.     

无皂乳液聚合中单分散粒子的形成过程

在少量双官能团水溶性共单体(磺化丁二酸-聚乙二醇-烯丙基缩水甘油醚酯)存在下进行MMA/BA无皂乳液聚合,用CoulterLS230激光粒径分析仪研究了乳胶粒子的成核机理和单分散粒子的形成过程.乳胶粒子的成粒过程属多步成粒机理:先均相成核,形成不稳定的初始粒子,然后凝聚成稳定乳胶粒,其粒径分布经历了先变宽后变窄的过程,这是聚合过程中成核-凝聚-增长共同作用,相互竞争的结果.它还导致聚合初期出现周期成核的现象.     

Hematite nanoparticles as polystyrene microsphere coatings and hollow spheres: preparation and characterization

A novel method of fabricating composite particles with core–shell structures is demonstrated. The particles comprised monodisperse submicrometer-sized copolymer latex spheres as cores and Fe₂O₃ crystallites as shells. The shell was formed by controlled hydrolysis of aqueous iron solutions, and the growth of hematite on the surface of the copolymer spheres was controlled by slow injection. Hollow spheres were obtained by calcinations of the so-coated copolymer lattices at 500°C in air. The void size of these hollow spheres was determined by the diameter of the copolymer template, and the wall thickness could be easily controlled in the range of 20–60 nm by using this coating process. The structure and the composition of the spheres were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). It can be seen that a crystallite change and a crystal phase transformation occurred during coating and calcination of the composite spheres. The formation of the composite particles is simply explained by the nucleation of iron oxide on the surface of the latex followed by growth of the iron compound shell.     

Drying dissipative structures of thermosensitive gel spheres of poly (N-isopropylacrylamide). Influence of gel size

Drying dissipative patterns of de-ionized suspensions (colloidal crystal-state at high concentrations) of the thermosensitive gels of poly (N-isopropylacrylamide) with various sizes (ca. 400–1,500?nm in diameter at 20?°C) were observed at 20 and 45?°C on a cover glass, a watch glass, and a Petri glass dish. The broad rings were observed and their size decreased as gel concentration decreased. Formation of the monodispersed agglomerated particles and their ordered arrays were observed irrespective of gel size. The macroscopic flickering spoke-like patterns were observed for the gel spheres from 70 to 600?nm in diameter at 20?°C, but almost disappeared for extremely large spheres, poly(N-isopropylacrylamide)(1500-5). This work clarified the formation of the drying microscopic structures of (a) ordered rings, (b) flickering ordered spoke lines, (c) net structure, and (d) lattice-like ordered structures of the agglomerated particles. The ordered rings became rather vague as gel size increased. The large net structures formed so often for large gels. Size effect on the lattice patterns was not recognized so clearly. The role of the electrical double layers around the agglomerated particles and the interaction of the particles with the substrate surfaces during dryness are important for the ordering. The microscopic drying patterns of gel spheres were quite different from those of linear type polymers and also from typical colloidal hard spheres, though the macroscopic patterns such as broad ring formation at the edges of the dried film were similar to each other.     

胶质碳球为模板制备NiO空心球

以胶质碳球为模板、六亚甲基四胺为沉淀剂,在乙醇中溶剂热反应,再经500℃煅烧6 h制备了NiO空心球。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅里叶变换红外光谱(FTIR)和低温氮吸附-脱附,对NiO的结构和形貌进行了表征。结果表明溶剂热反应时间是制备完整NiO空心球的关键因素,溶剂热反应12 h,再经空气中煅烧,可制得形貌均一的NiO空心球。所得产物是由NiO纳米粒子组装而成的具有多孔结构的空心球。同时,本文对NiO空心球结构的形成过程和可能机理进行了分析和讨论。     

Preparation of supported mesoporous thin films concerning template removal by supercritical fluid extraction

Thin films of silicate MCM-41 and silicate MCM-48 have been prepared on porous ceramic supports by the hydrothermal method. A comparative study of template removal has been made on supported thin films and on powder. By supercritical fluid extraction (SFE) with CH(3)OH-modified CO(2), at least 78% of the template can be removed from as-synthesized materials at 85 degrees C. X-ray diffraction (XRD) observations indicate that the resulting supported thin films after SFE are structurally stable and ordered with a weak pore contraction. The advantages of SFE over calcination in template removal are presented with a series of results obtained on supported thin films and on powder by XRD and N(2) adsorption-desorption.     

利用二氧化硅欧泊模板合成三维多孔金属镍

金属镍在高效催化剂、传感器、导电浆料、高密度磁记录材料、高性能电极材料等领域具有广阔的应用前景,在材料科学和凝聚态物理领域引起了广泛的研究兴趣。多孔金属镍结构由金属镍骨架及孔隙所组成,与致密块体镍相比,其内部具有大量的孔隙,因而具有诸多优异的特性,如密度小、比表面积大、光学性能优异等。多孔金属镍可用来制作过滤器、催化剂及催化剂载体、多孔电极等[1]。1987年Yablonovitch[2]和John[3]几乎同时提出了光子晶体这一新概念和新材料。构成三维模板的途径之一是在液体中自组装成具有光波量级的单分散胶体微球——胶体晶体,这…     

General and Facile Syntheses of Metal Silicate Porous Hollow Nanostructures

Porous hollow nanostructures have attracted intensive interest owing to their unique structure and promising applications in various fields. A facile hydrothermal synthesis has been developed to prepare porous hollow nanostructures of silicate materials through a sacrificial‐templating process. The key factors, such as the concentration of the free metal cation and the alkalinity of the solution, are discussed. Porous hollow nanostructures of magnesium silicate, nickel silicate, and iron silicate have been successfully prepared by using SiO₂ spheres as the template, as well as a silicon source. Several yolk–shell structures have also been fabricated by a similar process that uses silica‐coated composite particles as a template. As‐prepared mesoporous magnesium silicate hollow spheres showed an excellent ability to remove Pb²⁺ ions in water treatment owing to their large specific surface and unique structures.     

Drying dissipative structures of lightly cross-linked poly(2-vinyl pyridine) cationic gel spheres stabilized with poly(ethylene glycol) in the deionized aqueous suspension

Drying dissipative patterns of deionized and colloidal crystal-state suspensions of the cationic gel spheres of lightly cross-linked poly(2-vinyl pyridine) stabilized with poly(ethylene glycol) were observed on a cover glass, a watch glass, and a Petri glass dish. Convectional patterns were recognized with the naked eyes. The broad rings were observed in the drying pattern and their size and width decreased as gel concentration decreased. Formation of the monodispersed agglomerated particles and their ordered arrays were observed. This work clarified the formation of the drying microscopic structures of (a) ordered rings, (b) flickering ordered spoke-lines, (c) net structure, and (d) lattice-like ordered structures of the agglomerated particles. The ordering of the agglomerated particles of the cationic gel spheres is similar to that of the anionic thermo-sensitive gel spheres of poly(N-isopropyl acrylamide). The role of the electrical double layers around the agglomerated particles and the interaction of the particles with the substrates during dryness are important for the ordering. The microscopic drying patterns of gel spheres were different from those of linear-type polymers and also from typical colloidal hard spheres, though the macroscopic patterns such as broad ring formation at the edges were similar to each other. The addition of sodium chloride shifted the microscopic patterns from lattice to net structures.     

Effect of Deproteinized Methods on the Proteins and Properties of Natural Rubber Latex during Storage

Summary: Three different methods of deproteinization, i.e. saponification, surfactant washing and enzymatic treatment were employed to unravel the effect of deproteinized on the properties of natural rubber (NR) latex. The cleavage of proteins in NR latex was found to proceed with concomitant formation of low molecular weight polypeptides. This results in a lowering in gel formation of the enzyme-treated latex, indicating modification of the remaining proteins at the rubber chain-end. Washing NR latex with surfactant would efficiently reduce and remove proteins from NR latex particles through denaturation and transferring them to the serum phase. The relatively stable gel formed during storage of surfactant-washed NR latex is an indication of the absence of branch formation of proteins at the rubber molecule terminal. Saponification by strong alkali would hydrolyze the proteins and phospholipids adsorbed on the latex particle surface. The reason of the significantly higher gel formed in saponified NR latex is still not clear. The present study shows that deproteinization treatments result in modification of the proteins at the surface of NR latex particles and also those freely-suspended in the serum. The cleavage or the denaturation of the rubber proteins during purification by washing has a profound effect on the properties of the deproteinized NR latex upon storage, in particular the thermal oxidative aging properties of the rubber obtained.