Structure and optical properties of ordered mesoporous copper oxide–silica composite films

In this study, ordered mesoporous copper oxide–silica (CuO–SiO₂) composite films with CuO/SiO₂ molar ratio ≤6% have been prepared. Small-angle X-ray diffraction and transmission electron microscopy investigations show that the mesoporous CuO–SiO₂ composite films have a hexagonally ordered pore array nanostructure. Wide-angle X-ray diffraction analysis reveals that the copper oxide and silica in the composite films are non-crystalline. The non-crystalline CuO in the mesoporous composite films has an obvious blue-shift phenomenon of the absorption edge. The calculated band gap energy for CuO is 3.2?eV, which is much higher than its bulk counterparts (1.21–1.5?eV).     

电化学制备有序聚苯胺／聚苯乙烯复合材料

利用垂直沉积自组装技术在氧化铟锡（ITO）导电玻璃基底上制备出高度有序的聚苯乙烯（PS）薄膜,以此为模板,在三电极体系中应用循环伏安法,控制电势在-0．3-0．9V之间,以20mV／S的扫描速度,在有序排列PS薄膜的表面电化学沉积聚苯胺（PANI）,成功制备出了聚苯胺／聚苯乙烯（PS／PANI）有序导电高分子复合材料,通过紫外-可见光分光光度计、循环伏安法、场发射扫描电镜、x射线衍射仪进行表征,结果表明,制得的PS／PANI复合材料粒径均匀、排列有序、呈密堆积结构,可为制备具有有序中空或大孔膜产物提供较理想的模板。     

云母的磁改性及其聚合物有序复合材料的制备

通过磁场诱导，制备了环氧树脂／云母高度取向复合材料．采用化学共沉淀法，先在云母表面包覆上一层强磁性纳米粒子．将磁改性云母分散在环氧树脂基体中，在外加磁场诱导下，云母在基体中沿一定方向取向排列。通过SEM，XRD等表征手段对样品的形貌和结构进行了分析，结果表明，云母片在基体中彼此平行排列．     

Self-Organization of Detonation-Diamond Particles on a Substrate in Carbon Condensation from the Vapor–Gas Phase

Technical Physics Letters - Processes in which the island structure is ordered occur in composite carbon films produced by preliminary population of an amorphous substrate with a detonation-diamond...     

Effects of substrate and orientational property of liquid crystal domains on the blood compatibility of polymer/liquid crystal composite membranes

A series of polymer/cholesteryl liquid crystal (LC) composite membranes were prepared. Polyurethane and polyvinyl chloride, as a substrate, were blended with cholesteryl tetraethylene glycol carbonate to form composite membranes in an electric field under normal conditions. The blood compatibility of composite materials was identified by the dynamic blood-clotting test, haemolysis ratio measurement, platelet adhesion and SEM observation. The results showed that the content of LC, the ordered extent of LC domains embedded in composite materials and the type of substrate have greater effects on the blood compatibility of polymer/LC composite materials. When the LC domains were properly oriented, polymer/LC composite membranes had an excellent haemocompatibility, fewer platelets were adhered and spread and showed little distortion on the surface of materials.     

颗粒团聚分布的复合材料数值模型

目的 提出颗粒团聚分布的数值模型参数化建模方法,以高效建立颗粒有序分布的复合材料微观构型。方法 以颗粒尺寸、颗粒团聚区域的半径以及团聚区域局部体积分数和整体体积分数的比值作为表征颗粒团聚结构的基本建模控制参数,首先建立了圆形/球形区域内的Voronoi多胞元结构,其次编写基于Python语言的接口程序,根据角点坐标和几何拓扑关系将多胞元结构导入有限元软件中,并对每个胞元按团聚区域局部体积分数进行缩放,形成了圆形/球形区域的颗粒团簇,最后使用随机顺序吸附算法将团聚颗粒在代表单元内周期性随机投放,生成了颗粒团聚分布的复合材料二维/三维微观构型。结果 使用不同控制参数进行数值建模测试,生成一个颗粒数目在1 000以内的二维/三维颗粒团聚微观构型仅需要数分钟,验证了本文方法的有效性。使用二维模型对单轴拉伸进行数值模拟,结果表明,材料宏观塑性随着颗粒团聚程度的增大而降低。结论 本文建模方法可以为复合材料结构设计提供有效的数值仿真支撑。     

CeO2 / TiO2 复合体系的有序介孔结构表征

通过有机模板-溶剂热-超临界流体干燥法获得四方相TiO₂有序介孔(2～4 nm) 粉体, 利用浸泡沉淀法将CeO₂ 填充到TiO₂的介孔孔道中, 并用HREM、TEM、BET 等分析技术, 对CeO₂ / TiO₂ 复合体系的有序介孔结构进行了表征, 初步探讨了TiO₂ 介孔结构和CeO₂ 纳米团簇结构的形成机理。结果表明, 所制备的CeO₂ /TiO₂ 体系实现了纳米尺寸结构的均匀复合。      

Oriented polythiophene nanofibers grown from CdTe quantum dot surfaces

Highly crystalline, doped polythiophene is grown from the surfaces of CdTe quantum dots by ligand exchange of 3-thenoic acid followed by an oxidant-initiated polymerization. The facile synthesis generates a composite of highly ordered fibers, which exhibit efficient charge transfer between the polythiophene and the inorganic CdTe quantum dots.     

Determining conditions for the preparation of polymer films containing an ordered structure of carbon nanotubes and higher fullerenes

The experimental conditions necessary for the preparation of polymeric composite films (membranes) containing an ordered structure of single-wall carbon nanotubes and higher fullerenes are determined. The films are obtained by ordering a homogeneous suspension of carbon nanotubes and fullerenes in the initial liquid prepolymer or monomer, followed by curing of the matrix. The parameters of ordering (duration, field strength) are estimated, which make possible realization of the proposed process for the preparation of carbon-containing composite films based on polymer matrices of the polycyanurate type.     

Self-adjusted synthesis of ordered stable mesoporous minerals by acid-base pairs

Although the chemical diversity of ordered composite mesoporous materials has been expanding during the past decade, progress has been limited by the need for a general synthetic approach that is predictive and makes use of well developed fundamental chemical principles. Researchers have previously used the interaction of organic-inorganic (OI) species that are present during the nucleation of the composite phase, and several synthesis pathways, such as direct surfactant-inorganic interaction (S+I-, S-I+, S0I0) and mediated interaction (S+X-I+, S-X+I-), have been proposed. Here we describe a new perspective in which the self-adjusted inorganic-inorganic (II) interplay between two or more inorganic precursors is guided by acid-base chemistry considerations, and in this simple way we produce an overall 'framework' for the sophisticated combination of synergic inorganic acid-base precursor pairs. We propose several new routes and demonstrate their versatility and validity through the successful syntheses of a wide variety of highly ordered, large-pore, homogeneous, stable and multicomponent mesostructured minerals, including metal phosphates and metal borates, as well as various metal oxides and mixed metal oxides. We show that the highly ordered mesostructured metal phosphates can be moulded into morphologies of choice, and that they show interesting physicochemical properties.     

Quasi-one-dimensional distribution of macropores in anodically etched uniaxially stressed silicon plates

Gradual transition from quasi-hexagonal to quasi-one-dimensional order was experimentally observed in an arrangement of macropores etched on the surface of a Si(100) plate inhomogeneously strained by bending. The observed phenomenon is theoretically described within the framework of a defect-deformation mechanism of the formation of ordered ensembles of seeding pores in etched semiconductors and metals.     

Characterization and magnetic properties of conducting poly(N-vinylcarbazole)-capped magnetite nanocomposite Langmuir-Schaefer films

Functionalized poly(N-vinylcarbazole) (PVK) has been synthesized by an oxidative polymerization with capped magnetite nanoparticles (CMPs, 10, 20, and 30%) for the preparation of conducting polymer composites that possess both electrical and magnetic properties. Spectroscopic studies reveal the successful functionalization of the nanoparticles into the PVK matrix. I-V characteristics of the composite films show an increase in the conductivity of the PVK film due to the presence of CMPs. The magnetization data exhibit an appreciable hysteresis loop at room temperature. The composite samples reveal an ordered semi-conducting behavior.     

Detection of Defect‐Induced Magnetism in Low‐Dimensional ZnO Structures by Magnetophotocurrent

The detection of defect‐induced magnetic order in single low‐dimensional oxide structures is in general difficult because of the relatively small yield of magnetically ordered regions. In this work, the effect of an external magnetic field on the transient photocurrent measured after light irradiation on different ZnO samples at room temperature is studied. It has been found that a magnetic field produces a change in the relaxation rate of the transient photocurrent only in magnetically ordered ZnO samples. This rate can decrease or increase with field, depending on whether the magnetically ordered region is in the bulk or only at the surface of the ZnO sample. The phenomenon reported here is of importance for the development of magneto‐optical low‐dimensional oxides devices and provides a new guideline for the detection of magnetic order in low‐dimensional magnetic semiconductors.     

TiO2-聚吡咯纳米复合材料的电化学制备及其在锂硫电池中的应用

采用电化学沉积的方法,以阳极氧化法制备的二氧化钛纳米管阵列为基底,制备出高度有序的TiO_2-聚吡咯(PPy)纳米阵列,再通过共热法,将单质硫颗粒负载到基底阵列中,得到S/PPy/TiO_2纳米阵列结构复合材料。扫描电镜(SEM)、透射电镜(TEM)、能谱(EDX)、傅里叶变换红外光谱(FT-IR)和热重分析(TGA)表征结果表明,TiO_2纳米管高度有序平行排列,管径约120nm,聚吡咯均匀沉积在纳米管壁上,复合材料中硫的质量分数约为61.9%。电化学测试结果表明,在0.1C电流密度下,S/PPy/TiO_2纳米复合材料首次循环比容量达1155mAh·g-1,100次循环后比容量为648.4mAh·g-1,库伦效率保持在96.8%。高容量下良好的循环稳定性能显示出S/TiO_2/PPy纳米阵列结构复合材料作为锂硫电池正极材料的优势。     

Preparation of conductive transparent adhesive films from carbon nanomaterials and polar acrylate

Electrically conductive optically clear adhesives (ECOCAs) were prepared using a nanostructured carbon material (CMK-3(150)) as a conductive filler. The mesoporous carbon material, CMK-3(150), was synthesized using an ordered mesoporous silica template to produce inverse replica ordered mesoporous carbon material with an approximately 10 nm pore diameter. An adhesive solution of acrylic monomers containing polar acrylate, CMK-3(150), and thermal initiator was reacted at 80 degrees C to prepare the ECOCA composite which had appropriate viscosity for further processing. The adhesive composite was adhered to various surfaces including ITO films upon thermal processing at 60 degrees C to afford a highly transparent and adhesive film. Tensile strength of the ECOCA films was increased with the contents of conductive filler up to 4 wt%. The percolation concentration of the CMK-3(150) in the composite was approximately 7 wt%, which is much less than those of typical conductive fillers. The optimum content of CMK-3(150) to assure optical clarity, tensile strength, and high conductivity was 2-3 wt%.     

Poly(vinyl alcohol)–hydroxyapatite biomimetic scaffold for tissue regeneration

Hydroxyapatite–poly(vinyl alcohol) composite blocks were produced by freeze–thawing in situ synthesized hybrid suspension. Matrix mediated precipitation of hydroxyapatite particles in the polymer, controlled the particle size in nanometer range (< 100 nm) and hydrogelation induced an ordered three-dimensional assembly of the particles. Morphological and crystallographic characterization revealed the formation of a macro-porous hydroxyapatite–poly(vinyl alcohol) nanocomposite block. Initial results indicate compositional dependence of modulus of elasticity of the composite.     

Template-free synthesis of ordered mesoporous NiO/poly(sodium-4-styrene sulfonate) functionalized carbon nanotubes composite for electrochemical capacitors

We report the first example of a practical and efficient template-free strategy for synthesizing ordered mesoporous NiO/poly(sodium-4-styrene sulfonate) (PSS) functionalized carbon nanotubes (FCNTs) composites by calcining a Ni(OH)₂/FCNTs precursor prepared by refluxing an alkaline solution of Ni(NH₃) _x ²⁺ and FCNTs at 97 °C for 1 h. The morphology and structure were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Thermal decomposition of the precursor results in the formation of ordered mesoporous NiO/FCNTs composite (ca. 48 wt% NiO) with large specific surface area. Due to its enhanced electronic conductivity and hierarchical (meso- and macro-) porosity, composite simultaneously meets the three requirements for energy storage in electrochemical capacitors at high rate, namely, good electron conductivity, highly accessibleelectrochemical surface areas owing to the existence of mesopores, and efficient mass transport from the macropores. Electrochemical data demonstrated that the ordered mesoporous NiO/FCNTs composite is capable of delivering a specific capacitance (SC) of 526 F/g at 1 A/g and a SC of 439 F/g even at 6 A/g, and show a degradation of only ca. 6% in SC after 2000 continuous charge/discharge cycles.      

An Unusual Mechanism of Misfit Stress Relaxation in Thin Nanofilms

Technical Physics Letters - A new mechanism of misfit stress relaxation in nanofilms with variable density of surface phases is established. This phenomenon is ensured by ordered mass transfer of...     

TiO_2纳米管/介孔SiO_2复合膜的制备及生物活性研究

以表面构筑了TiO2纳米管阵列的金属钛为基底,采用溶胶-凝胶工艺和浸渍-提拉技术涂覆介孔SiO2薄膜,构建了TiO2纳米管/介孔SiO2复合膜。利用SAXRD、FTIR、HRTEM和FESEM等表征样品的结构和微观形貌。研究表明,在高度有序、规整排列的TiO2纳米管阵列基底上,利用溶胶-凝胶工艺和浸渍-提拉技术涂覆有六方相介孔SiO2薄膜的复合膜具有良好的生物活性。