仿贝壳结构的自组装有机-无机纳米复合薄膜的制备及结构表征

利用超分子自组装法在玻璃表面制备了聚合前后 DMTB/Si O2 和 DMCB/Si O2 复合薄膜 .在所制备的复合薄膜中 ,表面活性剂 DMTB和 DMCB既作结构导向剂 ,又作聚合单体 .用 FTIR,XRD和 TEM等表征了薄膜的结构 .结果表明 ,所制备的薄膜具有有机 -无机有序交替的层状结构 .DMCB/Si O2 和 DMTB/Si O2复合薄膜有机层与无机层间的距离分别为聚合前 3 .48和 3 .44nm,聚合后 2 .84和 2 .92 nm.     

仿贝壳自组装纳米复合薄膜的制备及结构表征

利用超分子自组装方法在普通玻璃表面制备了仿贝壳有机 无机复合纳米薄膜.采用X射线衍射仪、傅立叶红外光谱仪、紫外 可见吸收光谱仪、透射电子显微镜对薄膜结构进行了表征.结果表明这种薄膜具有有机 无机有序交替的层状纳米复合结构，聚合前层间距为4.20 nm，聚合后层间距为3.91 nm.无机层由TiO2纳米微粒构成.     

仿贝壳结构的自组装纳米复合薄膜的制备、表征及摩擦学性能研究

利用超分子自组装方法在普通玻璃表面制备了仿贝壳有机-无机复合纳米薄膜 。采用X射线衍射仪、傅立叶红外光谱仪、X射线光电子能谱仪及透射电子显微镜等 对薄膜结构进行了表征。用动-静摩擦系数测定仪初步考察了其摩擦行为。结果表 明,这种薄膜具有机-无机有序交替的层状纳米复合结构,其聚合前的层间距为4. 20 nm, 聚合后的层间距为3.91 nm。聚合后的仿贝壳自组装纳米复合薄膜具有良好 的减摩性能。     

对称性降低的SiO2/Ag核壳结构纳米粒子的制备及表面增强拉曼活性研究

采用湿化学还原法在自组装的单层阵列二氧化硅纳米粒子表面沉积银膜制备了SiO2核/Ag帽复合纳米结构。通过透射电镜(TEM)、扫描电镜(SEM)、X射线衍射(XRD)和紫外-可见分光光度计(UV/Vis)研究和表征了该复合纳米结构的表面形貌、结构及光学性质。所制备的复合纳米粒子表面粗糙,其表面呈现无数纳米级谷粒状结构,SiO2内核粒径为350nm的银纳米帽的表面等离子共振吸收的2个共振峰分别位于382和689nm处。以亚甲基蓝作为探测分子研究了SiO2粒径为350和450nm的SiO2/Ag帽状复合纳米粒子的表面增强拉曼散射(SERS)活性,增强因子分别为3.6×109和3.9×109。结果表明,湿化学还原法制备的SiO2核/Ag帽复合纳米结构是很好的拉曼活性基底。     

Ag-PVA和Ag-PVA/TiO2复合超薄膜的制备及性能研究

用3种方法制备了银纳米粒子-聚乙烯醇复合体系,其中用加热还原法所得体系中Ag纳米粒子的尺寸较大(15nm),其表面等离子体共振吸收峰较宽,最大吸收波长位于420nm;用室温硼氢化钠还原法得到的复合体系的吸收峰蓝移至409nm,且峰形较窄,Ag纳米粒子的平均粒径为8.7nm;低温NaBH4还原法所得体系吸收峰进一步蓝移至397nm,此时Ag纳米粒子粒径最小(3.5nm).将室温还原法所得Ag-PVA复合体系旋涂成膜,所得薄膜光滑、透明、均匀性好,该法适用于制备多层薄膜,以调控薄膜的厚度和光谱性质.将Ag-PVA复合体系与钛酸四丁酯(Ti(O_nBu)₄)的乙醇溶液交替旋涂得到Ag-PVA/TiO₂有机/无机复合薄膜.紫外-可见吸收光谱研究表明,随着Ag-PVA层数的增加,薄膜的表面等离子体共振吸收强度呈线性增加,但是TiO₂层数的增加对吸收光谱没有明显影响.Ag-PVA/TiO₂有机/无机复合薄膜将金属纳米粒子、有机高分子与无机半导体材料结合在一起,这种多层纳米结构在光电、催化功能薄膜等方面具有潜在的应用前景.     

二氧化钛/聚乙烯吡咯烷酮纳米复合薄膜的制备与表征

采用溶胶-凝胶法(so1 gel)制备了TiO2/聚乙烯吡咯烷酮(PVP)有机 无机纳米复合薄膜.采用扫描电子显微镜、接触角测定仪、红外光谱仪、紫外 可见吸收光谱仪和静 动摩擦系数测定仪对所制备的TiO2/PVP纳米复合薄膜进行了结构表征和性能研究.结果表明:所制备的TiO2/PVP纳米复合薄膜表面平整光滑、无裂纹、具有一定的疏水性、良好的透明性、防紫外线性能和减摩抗磨性能.     

新型室温酯化法接枝聚合物改性SiO_2纳米微粒

提出了一种在室温、大气环境等温和条件下通过酯化反应将端羧基聚合物链接枝到纳米SiO2微球表面从而制备有机/无机复合纳米微粒的新方法.该方法通过以下两个步骤得以实现,即第一,用3-环氧丙基三甲氧基硅烷对纳米SiO2微球表面进行改性处理,接着将引入到纳米SiO2表面的环氧基团转化为烷羟基基团;第二,通过引入到纳米SiO2微球表面的烷羟基与聚合物中的端羧基在室温下发生酯化反应,从而将聚合物接枝到纳米SiO2表面制得复合微球.利用XPS、FTIR、TEM和TGA等测试手段对纳米SiO2的改性过程以及聚合物接枝后得到的复合微球进行了表征.研究结果表明,该室温酯化接枝方法具有较高的接枝率,接枝到无机纳米微粒表面的聚合物占复合微球质量的55wt%～70wt%;接枝聚合物后,纳米SiO2微球的粒径从40nm增加到64～75nm,从而得到了以SiO2为核、以聚合物为壳的有机-无机复合微球.     

二氧化硅纳米粒子薄膜的制备及光学性能

以二氧化硅胶体和聚二烯丙基二甲基氯化铵(PDDA)为原料,利用静电自组装技术制备了PDDA/SiO2复合薄膜. TEM图象显示,薄膜中的SiO2纳米粒子为密堆积,薄膜均匀、致密;电子衍射实验结果显示,所组装的薄膜为非晶态膜.载玻片表面组装SiO2纳米粒子薄膜后,透射率随薄膜双层数增加呈现周期变化.薄膜具有增透作用,载玻片双面组装薄膜后在一定波长范围内的透射率可提高5％以上. PDDA/SiO2复合薄膜的光学性质主要由SiO2纳米粒子决定,每一双层的平均物理厚度小于SiO2纳米粒子的粒径,薄膜中存在层间穿插现象,逐层组装的复合薄膜具有单层光学薄膜的特性.     

表面修饰二氧化钛纳米粒子的结构表征及形成机理

利用溶胶 凝胶法在混合溶剂中制备了硬脂酸表面修饰TiO2纳米粒子,对所合成的纳米粒子通过FTIR、XPS、XRD和TEM对其结构进行表征.结果确证了表面有机修饰层的存在,并且是羧酸根与无机内核以双齿配位形式结合;无机纳米内核的结晶度很低,但是可以确定为锐钛矿成分,平均粒径约为6～8 nm.提出了表面修饰纳米粒子的形成机理,认为在体系中硬脂酸和水之间发生竞争反应,其过程类似于聚合 阻聚反应,最后给出了硬脂酸表面修饰TiO2纳米粒子的结构模型.     

TiO_2/SiO_2纳米薄膜的光催化活性和亲水性

通过 sol-gel工艺在钠钙玻璃表面制备了均匀透明的 TiO2/SiO2复合纳米薄膜 .实验结果表明 : 当 SiO2添加量较高时 , TiO2/SiO2复合纳米薄膜的光催化活性明显降低 ;当 SiO2添加量较低时 ,TiO2/SiO2复合薄膜的光催化活性无明显变化 .在 TiO2薄膜中添加 SiO2,可以抑制薄膜中 TiO2晶粒的长大 ,同时薄膜表面的羟基含量增加 , 水在复合薄膜表面的润湿角下降 , 亲水能力增强 .当 SiO2含量为 10％－ 20％（摩尔分数）时获得了润湿角为 0°的超亲水性薄膜 .     

层层沉积提高井壁稳定性室内研究

以钠蒙脱土分散液作为模拟钻井液,与支化聚乙烯亚胺聚合物溶液交替流过模拟井壁(硅片),模拟生物矿化过程,进行层层沉积模拟实验。通过原子力显微镜、扫描电镜、红外光谱、X射线衍射等手段跟踪钠蒙脱土/聚乙烯亚胺复合膜的成膜过程,并表征复合膜的形貌、微观结构、化学组成及力学性能。结果表明,钠蒙脱土和聚乙烯亚胺可自发在模拟井壁上形成结构致密的有机/无机复合膜,该复合膜具有明显的层状结构,平均每层厚度约为46.18nm。该复合膜力学性能优良,而且杨氏模量并不随沉积层数的增加而变化。通过动态滤失实验表明,层层沉积改善了滤饼质量,降低了滤失速率以及总的动态滤失量,有助于井壁稳定。     

Synthesis of nanostructured metal-organic films: surface X-ray radiolysis of silver ions using a langmuir monolayer as a template

An application of the radiolysis method using an X-ray synchrotron beam is developed as a novel approach to the synthesis of metal-organic films with controlled shapes and thickness. We demonstrate that a Langmuir monolayer deposited onto a silver ion containing subphase, irradiated by an incident beam impinging below the critical angle for total reflection, induces the synthesis of a stable nanostructured silver-organic ultrathin film at the air-water interface. The X-ray scattering is also used to monitor in situ the structure of the silver layer during the synthesis process. The layer is observed by atomic force microscopy after its transfer onto a silicon substrate. One observes a film thickness of 4.6 nm, in good agreement with the X-ray penetration depth, about 4.5 nm. The silver structure is oriented by the initial organic film phase. This experiment demonstrates the considerable potential of this approach to produce various controlled metal-organic films with a surfactant self-assembly as a template.     

The effect of water or salt solution on thin hydrophobic films

Hydrophobic films of polystyrene synthesized in bulk (PS) and by emulsion polymerization in the presence of the cationic surfactant cetyltrimethylammonium bromide (PS-CTAB) or the anionic surfactant sodium dodecyl sulfate (PS-SDS) were characterized by means of ellipsometry, contact angle measurements, and atomic force microscopy. Thin (approximately 65 nm) and thick (approximately 300 nm) films were spin-coated on hydrophilic silicon wafers. PS films presented scarcely tiny holes, while PS-CTAB and PS-SDS films presented holes and protuberances. The former were attributed to dewetting effects and the latter to surfactant clusters. The films were exposed to water or to a 0.1 mol/L NaCl solution for 24 h. Ex situ measurements evidenced strong topographic alterations after the exposure to the fluid. A model based on the diffusion of water (or electrolyte) molecules to the polymer/silcon dioxide interface through holes or defects on the film edges was proposed to explain the appearance of wrinkles and protuberances. In situ ellipsometric measurements were performed and compared with simulations, which considered either a water layer between a polymer and a silcon dioxide layer or an air layer between a polymer and water (medium). In the case of thin PS films, the ellipsometric angles evidenced a very thin (0.5-1.0 nm) air layer between water and the PS films. Upon increasing the PS film thickness, no air layer could be observed by ellipsometry. Regardless of the thickness, the ellipsometric data obtained for PS-CTAB and PS-SDS films did not indicate the presence of an air layer between them and the aqueous media. The dramatic changes in the topography of PS, PS-CTAB, and PS-SDS after immersion in salt solution were explained with proposed models. From a practical point of view, this study is particularly relevant because many hydrophobic polymers are used as substrates for biomedical purposes, where the physiological ionic strength is 0.15 mol/L NaCl.     

纳米ZnO薄膜的制备及其可见光催化降解甲基橙

采用溶胶-凝胶方法制备ZnO透明溶胶, 在铝箔上涂膜后经500 ℃处理制得具有可见光响应的纳米ZnO薄膜光催化剂. 以甲基橙模拟有机污染物, 在可见光下研究了薄膜的降解性能, 结果表明, 用一片有效面积为200 cm2的ZnO/Al薄膜作为催化剂, 甲基橙的降解率达到96.3％, 比ZnO负载在玻璃上制得的ZnO/glass薄膜催化剂活性高得多. 采用扫描电镜与原子力显微镜对ZnO/Al薄膜制备条件进行了表征, 结果发现多孔ZnO/Al薄膜比致密ZnO/Al薄膜具有更高的活性, 实验制备的具有高活性的ZnO/Al薄膜颗粒平均直径为52.2 nm. 采用本方法制备的ZnO/Al薄膜是一种具有应用前景的, 能在可见光下降解有机物的有效光催化剂.     

Preparation and characterization of thin films of SiO(x) on gold substrates for surface plasmon resonance studies

We report here on the fabrication and characterization of stable thin films of amorphous silica (SiO(x)) deposited on glass slides coated with a 5 nm adhesion layer of titanium and 50 nm of gold, using the plasma-enhanced chemical vapor deposition (PECVD) technique. The resulting surfaces were characterized using atomic force microscopy (AFM), ellipsometry, contact angle measurements, and surface plasmon resonance (SPR). AFM analysis indicates that homogeneous films of silica with low roughness were formed on the gold surface. The deposited silica films showed excellent stability in different solvents and in piranha solution. There was no significant variation in the thickness or in the SPR signal after these harsh treatments. The Au/SiO(x) interfaces were investigated for their potential applications as new surface plasmon resonance sensor chips. Silica films with thicknesses up to 40 nm allowed visualization of the surface plasmon effect, while thicker films resulted in the loss of the SPR characteristics. SPR allowed further the determination of the silica thickness and was compared to ellipsometric results. Chemical treatment of the SiO(x) film with piranha solution led to the generation of silanol surface groups that have been coupled with a trichlorosilane.     

Preparation, characterization, and application of polypropylene-clinoptilolite composites for the selective adsorption of lead from aqueous media

The miscibility, mechanical and morphological properties of mixed Langmuir and Langmuir-Blodgett monolayers prepared from the phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and the perfluorinated fatty acid perfluorooctadecanoic acid have been studied as a function of film composition and subphase salinity. It was demonstrated here, for the first time, that the extent of surfactant miscibility in mixed phospholipid-perfluoroacid monolayers, and hence the resulting mechanical properties of the monolayer film, can be controlled by altering the concentration of sodium ions in the underlying subphase. Elevated Na(+) concentrations resulted in lower net attractive interactions between film components, likely through specific ion adsorption to the negatively-charged perfluoroacid, along with decreased film elasticities. These results differ significantly from conventional fatty-acid-carboxylate monolayer systems in which film cohesion is typically enhanced through adsorption of cations to surfactant headgroups. Atomic force microscope images of films deposited onto solid mica substrates revealed that the films deposited from pure water formed multimolecular aggregates of surfactant, which could be attributed to the highly cohesive nature of the films, but the use of salt in the subphase diminished aggregate formation and resulted in the production of homogeneous monolayer films.     

Mechanical property and corrosion resistance of zirconia/polydopamine nanocomposite multilayer films fabricated via a novel non‐electrostatic layer‐by‐layer assembly technique

Zirconia/polydopamine (ZrO₂/PDA) nanocomposite multilayer films were constructed on Si substrate via a novel nonelectrostatic layer‐by‐layer (NELBL) assembly technique. The building block of this technique is the newly reported dopamine molecule, which can be attached to almost all material surfaces and undergo oxidation‐polymerization to form PDA layers; more importantly, the outer hydroxyl groups of the PDA layer can chelated with certain inorganic oxide nanoparticles to generate oxide films. Thus, ZrO₂/PDA nanocomposite multilayer films were fabricated by sequential NELBL deposition of PDA and ZrO₂ nanoparticles. The formation of the ZrO₂/PDA nanocomposite multilayer films was monitored by the water contact angle (WCA) and ellipsometric thickness measurements, while the microstructure of the fabricated films was analyzed by means of atomic force microscope (AFM), field emission scanning electron microscope (FESEM), X‐ray photoelectron spectrum (XPS), and X‐ray diffraction (XRD) analysis. The mechanical and anticorrosion behaviors of the annealed ZrO₂/PDA nanocomposite multilayers were found to be greatly enhanced as compared with that of the annealed homogeneous ZrO₂ film. The better mechanical and anticorrosion behaviors of the annealed ZrO₂/PDA nanocomposite multilayers than the annealed homogeneous ZrO₂ film may be closely related to their special microstructure. Namely, the organic–inorganic hybrid microstructure of the annealed ZrO₂/PDA nanocomposite multilayers may largely account for the increased nanohardness and corrosion resistance. Copyright © 2010 John Wiley & Sons, Ltd.     

Preparation and characterization of polymer/silica nanocomposites via double in situ miniemulsion polymerization

Polymer/SiO₂ nanocomposite microspheres were prepared by double in situ miniemulsion polymerization in the presence of methyl methacrylate, butyl acrylate, γ‐methacryloxy(propyl) trimethoxysilane, and tetraethoxysilane (TEOS). By taking full advantage of phase separation between the growing polymer particles and TEOS, inorganic/polymer microspheres were fabricated successfully in a one‐step process with the formation of SiO₂ particles and the polymerization of organic monomers taking place simultaneously. The morphology of nanocomposite microspheres and the microstructure, mechanical properties, thermal properties, and optical properties of the nanocomposite films were characterized and discussed. The results showed that hybrid microspheres had a raspberry‐like structure with silica nanoparticles on the shells of polymer. The silica particles of about 20 nm were highly dispersed within the nanocomposite films without aggregations. The transmittance of nanocomposite film was comparable to that of the copolymer film at around 70–80% from 400 to 800 nm. The mechanical properties and the fire‐retardant behavior of the polymer matrix were improved by the incorporation of silica nanoparticles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3128–3134, 2010