垂直沉积法制备二氢化硅胶体晶体及其表征

利用垂直沉积法将单分散的二氧化硅胶体微球自组装生长为胶体晶体，并用扫描电子显微镜和紫外—可见光分光光度计对其显微形貌和光学特性进行了表征．结果表明二氧化硅微球有序堆积，自组装成胶体晶体，其结构为FCC密排结构，表面为FCC密排结构的(111)面；反射光谱还表明，所制备的胶体晶体的光子带隙位于可见光波段．与重力沉淀等其他自组装方法相比，垂直沉积法制备胶体晶体具有能够用胶体微球粒径和胶体溶液浓度精确控制样品厚度等优点．     

垂直沉积法制备二氧化硅胶体晶体及其表征

利用垂直沉积法将单分散的二氧化硅胶体微球自组装生长为胶体晶体 ,并用扫描电子显微镜和紫外可见光分光光度计对其显微形貌和光学特性进行了表征 .结果表明二氧化硅微球有序堆积 ,自组装成胶体晶体 ,其结构为FCC密排结构 ,表面为FCC密排结构的 ( 1 1 1 )面 ;反射光谱还表明 ,所制备的胶体晶体的光子带隙位于可见光波段 .与重力沉淀等其他自组装方法相比 ,垂直沉积法制备胶体晶体具有能够用胶体微球粒径和胶体溶液浓度精确控制样品厚度等优点     

纳米银分散的玻璃反蛋白石结构的制备与表征

作者通过溶胶凝胶填充方法、利用胶体晶体为模板,制备纳米银掺杂的氧化硅反蛋白石结构.其中胶体晶体模板通过单分散的胶体微球以垂直沉积法自组装而成.由胶体晶体模板制得的反蛋白石结构拥有与胶体晶体反结构相同的长程有序,并反射不同的色彩,其反射光谱随角度变化并满足布拉格关系.     

微球尺寸对其超分辨成像性质的影响

采用自组装法制备了二维六角密排的胶体晶体样品.使用直径为1.97μm、3.35μm、4.87μm、7.27μm的二氧化硅微球,对上述胶体晶体样品进行了微球成像实验,观察到微球对样品具有放大作用.用酒精半浸没微球时,通过微球观察到样品的对比度显著提高.研究结果表明:小尺寸的微球更利于接受高频信息;微球在酒精半浸没的情况下能接受更多高频信息,因此显著提高像的对比度;且不同频率成份参与成像,微球对这些成份的放大率是不同的.     

单分散PS微球的制备及其胶体晶体的组装

无皂乳液聚合法制备了不同尺寸单分散的PS微球,采用离心法和垂直沉降法将之组装成具有光子带隙的人工欧泊.采用扫描电子显微镜(SEM)和可见-紫外光度计对PS胶体晶体的形貌、结构和光学性能进行了观察测试.结果表明厚度较大的PS胶体晶体可以通过离心法组装制得,当转速为1 000 r/min、干燥温度为40℃时可以组装得到高质量的PS胶体晶体,而垂直沉降法则较适合组装薄型的胶体晶体.从样品的光学特性讨论了适合组装的乳液固含量,改变组装胶体晶体的PS微球粒径可以得到不同的光带隙波长.     

垂直沉积法组装二元聚苯乙烯胶粒晶体

采用垂直沉积法组装了二元聚苯乙烯胶粒晶体,研究了两种聚苯乙烯胶体微球的粒径比、质量比、温度和分散介质中乙二醇含量等因素对二元聚苯乙烯胶粒晶体组装花样的影响.粒径比>4.45、质量比≥74∶26是形成面心立方二元聚苯乙烯胶粒晶体的必要条件.组装温度为60℃,分散介质中乙二醇质量分数为6%时,可得到更高质量的二元聚苯乙烯胶体晶体.胶体微球二元垂直沉积机理研究表明:两种聚苯乙烯胶体微球是同时在基片的表面进行组装的;胶体微球在介质中的布朗运动、沉降速率及其在基片表面的组装速率三者之间匹配越好,所得二元聚苯乙烯胶粒晶体质量越高.     

聚苯乙烯-甲基丙烯酸模板与SiO2空心微球可控性制备

利用无皂聚合和乳液聚合,制备了聚苯乙烯-甲基丙烯酸胶体模板.聚苯乙烯-甲基丙烯酸胶体模板粒径分别控制为363,349,160和56 nm,实现了模板粒径的可控制备.利用制备的聚苯乙烯-甲基丙烯酸系列胶体模板,以偏硅酸钠为前驱体,煅烧去除模板后,制备了不同粒径及壁厚的二氧化硅空心微球.所制备的样品粒径在69～ 405 nm之间,壁厚在11 ～27 nm之间变化.利用扫描电子显微镜、透射电子显微镜和傅立叶变换红外光谱仪,对乳液模板、核壳复合材料及二氧化硅空心球形貌进行了表征,提出了聚苯乙烯-甲基丙烯酸模板与二氧化硅空心微球粒径调控的有效方法.     

二氧化硅胶态晶体的合成

以正硅酸乙酯为原料，采用控制凝聚法制备出173nm和297nm两种不同粒径的单分散二氧化硅微球乳液，并在一定湿度和温度下，利用乳液的单分散性，在表面张力的驱使下完成微球的自组装，从而得到三维有序的二氧化硅胶态晶体。扫描电镜显示：晶体呈面心立方结构，晶体表面至现出鲜艳的颜色，其波长与微球的直径相对应。     

羧基化聚苯乙烯微球的快速自组装

使用无皂乳液聚合制备出单分散羧基化聚苯乙烯微球,并自组装成胶体晶体阵列.采用FT-IR,DLS和Zeta电位分析对所用羧基化微球进行了表征;通过扫描电子显微镜观察了制得的胶体光子晶体表面形貌.实验结果和根据布拉格方程计算所得数据基本一致,证明该方法既可行又可靠.     

图纹结构Co/Pt多层膜的制备及垂直磁各向异性研究

采用自组装技术制备大面积有序聚苯乙烯微球模板.在此基础上,制备Co/Pt多层膜纳米碗列阵阵列.利用扫描电子显微镜(SEM)和振动样品磁强计(VSM)对样品表面形貌和磁性进行了分析.结果表明:纳米碗阵列保留了聚苯乙烯微球模板的有序形貌.磁性多层膜随着Pt或Co厚度的增大,矫顽力和Mr/Ms变化的总体趋势是先增大后减小.随着衬底胶体球半径的增加,曲率诱导作用逐渐减弱,矫顽力降低.     

PMMA胶体晶体模板法制备三维有序大孔TiO_2/SiO_2

以密堆积的聚甲基丙烯酸甲酯微球为模板,用一种预制备的水分散性TiO2纳米晶、正硅酸乙酯、水和乙醇制成混合溶胶,通过一种浸渍-抽滤方法,将混合溶胶充填于模板微球之间的间隙,原位形成凝胶,最终通过焙烧除去模板微球得到三维有序大孔TiO2/SiO2复合氧化物。样品的SEM结果表明,所形成的球形孔大小均匀,孔径在195$5nm,并以六方和四方的有序排列在三维方向上延伸。样品的TEM和XRD表明大孔的孔壁中含有6～7nm的锐钛矿型TiO2纳米晶。     

Synthesis of 3D ordered porous polystyrene using silica template

A rigid colloidal silica template was formed by self-assembly of the monodispersed silica spheres prepared according to Stober method. The silica template is highly ordered, which was verified by bright color effect due to Bragg diffraction and the results of SEM. The free radical polymerization of styrene was allowed within the interstices of the rigid template to result in the formation of the three-dimensional periodic silica/polystyrene nano-composites. The titled porous polystyrene was prepared by chemical decomposition of the template with concentrated aqueous hydrofluoric acid. Scanning electron microscopy characterization showed that the macroporous polystyrene has ordered arrays of the uniform pores replicated from the template. Moreover, it was found that the morphology of the as-synthesized macroporous polystyrene was greatly affected by the connectivity of the silica spheres treated under different conditions.     

8-羟基喹啉插层双氢氧化膜与溶胶–凝胶涂层对镁合金的腐蚀防护性能研究

采用8-羟基喹啉（8-HQ）插层双氢氧化物（LDH）膜为底层和溶胶–凝胶层相结合的方法,对AM60B镁合金进行了腐蚀防护性能的研究。采用扫描电子显微镜（SEM）、场发射扫描电子显微镜（FESEM）、能量色散X射线能谱（EDS）、X射线衍射（XRD）、原子力显微镜（AFM）和电化学阻抗谱（EIS）等方法对LDH、LDH/溶胶–凝胶和LDH@HQ/溶胶–凝胶涂层进行分析。SEM图像显示,垂直生长的纳米片组成的LDH膜完全覆盖在表面。LDH/溶胶–凝胶和LDH@HQ/溶胶–凝胶涂层的形貌相同。此外,除了LDH@HQ/溶胶–凝胶涂层具有相对较高的表面粗糙度外,两种复合涂层的形貌几乎相同。虽然在3.5wt% NaCl溶液中,LDH膜具有与合金样品相同的阻抗行为,但其耐蚀性要高得多,这可能是由于其阻隔性以及对氯离子的捕获。与LDH薄膜相似,随着暴露时间的延长,LDH/溶胶–凝胶复合材料的耐蚀性降低。但其值远高于LDH膜,这主要与溶液路径的封闭有关。LDH@HQ/溶胶–凝胶复合材料的抗腐蚀性能优于LDH/溶胶–凝胶涂层,原因是8-HQ通过络合作用吸附在损伤部位。     

纳米银明胶复合膜的制作

报道一种制备高浓度纳米银粒子的方法．通过化学溶胶法制备出纳米银溶胶粒子,再以热的明胶作基质,以明胶包覆纳米银粒子,加热浓缩,制备出高浓度纳米银粒子复合膜．电镜照片表明,纳米粒子并没有长大而聚沉,粒子尺度平均约为２０ｎｍ．     

纳米结构TiO_2微孔复合膜涂膜液的研制

用异丙醇钛经溶胶 -凝胶过程制得了二氧化钛粒子溶胶 ,发现是由锐钛矿微晶组成的 ,溶胶中加入添加剂制得涂膜液在多孔AL2 O3 陶瓷支撑体上涂膜 ,可制得完整的复合TiO2 膜。     

Improvement of corrosion performance of 316L stainless steel via PVTMS/henna thin film

Metallic materials are the most used materials as orthopedic or dental implants due to their excellent mechanical properties. However they are not able to create a natural bonding with the mineralized bone and occasionally suffer localized corrosion. This work describes the electrochemical behavior of a hybrid sol–gel thin film with the addition of green inhibitor. These films enhance the ability of the implant to make a union with the existing bone and improve its resistance to aggressive environment. An ethanol solution of the polymerized vinyltrimethoxysilane (PVTMS) was mixed with an aqueous solution of henna extract (Lawsonia inermis) and refluxed to give homogeneous sols. Nanostructure hybrid PVTMS/henna thin films were deposited on the stainless steel 316L by spin-coating. The morphology, composition and adhesion of hybrid sol–gel coatings have been examined by SEM, EDX and pull-off test, respectively. Addition of high additive concentrations (0.1%) did not disorganize the sol–gel network. Direct pull-off test recorded a mean coating-substrate bonding strength larger than 20.6 MPa for the hybrid sol–gel coating. The effect of henna extract, with various added concentrations from 0.012% to 0.1%, on the anticorrosion properties of sol–gel films have been characterized by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in simulated body fluid (SBF) solution and has been compared to the bare metal. Henna extract additions (0.05%) have significantly increased the corrosion protection of the sol–gel thin film to higher than 90%. The in vitro bioactivity of prepared films indicates that hydroxyapatite nuclei can form and grow on the surface of the doped sol–gel thin films. The present study shows that due to their excellent anticorrosion properties, bioactivity and bonding strength to substrate, doped sol–gel thin films are practical hybrid films in biomedical applications.     

Diffusion of point defects in two-dimensional colloidal crystals

Uniform colloidal microspheres dispersed in a solvent will, under appropriate conditions, self-assemble into ordered crystalline structures. Using these colloidal crystals as a model system, a great variety of problems of interest to materials science, physical chemistry, and condensed-matter physics have been investigated during the past two decades. Recently, it has been demonstrated that point defects can be created in two-dimensional colloidal crystals by manipulating individual particles with optical tweezers. Direct imaging of these defects verified that their stable configurations have lower symmetry than the underlying triangular lattice, as predicted by numerical simulations for a number of two-dimensional systems. It was also observed that point defects can dissociate into pairs of well-separated dislocations, a topological excitation especially important in two dimensions. Here we use a similar experimental system to study the dynamics of mono- and di-vacancies in two-dimensional colloidal crystals. We see evidence that the excitation of point defects into dislocation pairs enhances the diffusion of di-vacancies. Moreover, the hopping of the defects does not follow a pure random walk, but exhibits surprising memory effects. We expect the results presented in this work to be relevant for explaining the dynamics of other two-dimensional systems.     

FeCl3/PVP胶体催化H2O2氧化苯乙烯为苯甲醛

采用水热合成方法制备FeCl3/PVP(聚乙烯吡咯烷酮)胶体催化剂.利用TEM和XRD对样品的结构和形貌进行表征.结果表明,不添加PVP,FeCl3水热后形成Fe8O16(OH)16Cl1.3化合物.加入一定量PVP均生成不同大小棒状胶粒的胶体.PVP的加入量1.3g,水热温度为100℃,水热时间为2h,制备的胶体的性质最为稳定,并且催化氧化苯乙烯的活性最佳.此条件下制备的催化剂在60℃,反应时间6h,催化剂用量0.8mL的条件下,FeCl3/PVP胶体催化剂表现出较好活性,苯乙烯转化率92.4%,苯甲醛选择性83.4%.     

基于溶胶-凝胶技术的硅钨杂多酸化学修饰电极的组装及其电化学催化

将Keggin型硅钨杂多酸SiO