纳米压电-声学-热学显微术及其应用研究

在原子力显微镜(Atomic force microscope,AFM)基础上发展起来的扫描探针显微术(Scanning probe microscope,SPM)已成为推动当今纳米科学发展的最重要技术,综述了在商用AFM平台上所发展的超高分辨压电响应力显微术(PFM)、低频高分辨扫描探针声学显微术(SPAM)、三倍频双探针扫描热学显微术(3ω-STh M)等先进扫描探针显微术的工作原理及其应用研究,显示了该先进扫描探针显微术在纳米结构及其与外场互作用的机电、弹性、热学、热电等综合物理特性原位表征的重要潜力。     

环境净化功能(Ce,Ag)/TiO_2纳米材料表面能带结构的研究

用扫描隧道显微镜 /扫描隧道谱 (STM /STS)技术 ,研究 (Ce ,Ag) /TiO2 纳米光催化材料的表面能带结构 .结果表明 :在纳米TiO2 中加入稀土元素和银制备的 (Ce ,Ag) /TiO2 光催化纳米材料TiO2 的表面禁带宽度可由 2 .9eV降到 2 .4eV ,而且增加了新能级Ecb=-1.0eV ,Evb=0 .9eV ,Eg=1.9eV ,能够实现在可见光条件下的光催化     

金红石型TiO_2(011)晶面的表面化学研究进展

综述了采用高分辨扫描隧道显微镜(STM)等表面技术和密度泛函理论(DFT)计算等手段对TiO2(011)晶面的表面化学研究的进展,重点介绍了(011)面的表面结构组成、乙酸分子的吸附及诱导重构现象、水分子的吸附及产生的吸附氢原子的迁移和反应等方面的研究成果,揭示了TiO2表面结构与其化学性质的相互关系,为在原子尺度上理解TiO2催化材料的作用机理创造条件。     

金纳米粒子的合成和应用

金纳米粒子以它独特的光学、电学和催化性质以及在纳米级电子线路中的应用潜力,受到人们越来越多的关注.主要介绍了金纳米粒子的合成方法(模板法、湿化学法、电化学法、扫描探针微影术、光化学还原法和声化学合成法等)、成长机理和应用,展望了金纳米材料未来的研究方向和发展趋势.     

碳纤维结构的常用表征技术

本文结合近几年的研究报道,归纳了决定碳纤维性能及应用的两个方面内部体结构和表面结构的一些常用表征技术。碳纤维聚集态的表征主要通过X-射线衍射（广角、小角）、电子衍射;碳纤维形态结构特征常用透射电子显微镜;碳纤维表面结构的表征方法有扫描电子显微镜（SEM）,原子力显微镜（ArM）,扫描隧道显微镜（STM）以及扫描力显微镜（SFM）。其中,SEM能够看到整个纤维的表面形貌,而AFM、STM、SFM用于表面几个纳米到几百个纳米范围的形貌分析。此外,表面化学状态（表面成分、表面官能团）表征主要依靠X光电子能谱。     

炭黑表面的纳米结构对橡胶的补强作用

通过扫描隧道显微镜(STM)技术了解到炭黑粒子表面的鳞片状石墨微晶组成的纳米级精细结构，并研究炭黑对橡胶的补强机理。研究表明，炭黑表面的纳米结构使橡胶分子链网络缠绕在炭黑表面，并将外来应力分散到其它分子网络上，共同分担应力，使橡胶弹性体体系不至于迅速破坏。     

Ni-SiC纳米复合镀层的制备及表征

介绍了Ni-SiC纳米复合镀层的制备流程和其中各环节的技术要点,并借助扫描电镜、X射线衍射仪、显微硬度计和摩擦磨损试验机对所制备的纳米复合镀层的微观结构、显微硬度和耐磨性进行表征。结果表明:采用优选的镀液配方和工艺参数组合,制备出结构紧致、性能优良的Ni-SiC纳米复合镀层。与Ni-SiC微米复合镀层相比,纳米复合镀层的相结构有所不同,出现(311)和(222)两个新晶面且在(111)和(200)晶面均呈现出择优取向,同时显微硬度和耐磨性也明显提高。     

溶胶-凝胶法制备MgxZn1-xO纳米材料

以硝酸锌(Zn(NO3)2·6H2O)、柠檬酸(C6H8O7·H2O)为主要原料,采用改进的溶胶一凝胶法合成了纳米ZnO.在此基础上,添加硝酸镁(Mg(NO3)2·6H2O)合成了MgxZn1-xO.利用X-射线衍射(XRD)、扫描电子显微镜(SEM)表征分析了煅烧温度和Mg掺杂量对产物的相组成及显微形貌的影响.结果表明,x≤10at%时,MgxZn1-xO属于六方纤锌矿结构,当x≥20at%时,MgxZn1-xO中除了具有属于六方纤锌矿结构的ZnO以外还有属于NaCl结构的MgO晶相存在.随煅烧温度的升高,MgxZn1-xO纳米颗粒逐渐长大.     

脉冲电沉积Ni-SiC纳米复合镀层的工艺及性能

采用脉冲电沉积技术在铜基表面制备Ni-SiC纳米复合镀层。利用扫描电镜(SEM)、透射电镜(TEM)、显微硬度计及电化学测试,研究了纳米SiC微粒的质量浓度对复合镀层的表面形貌、组织结构、显微硬度以及耐蚀性的影响。结果表明:当纳米SiC微粒的质量浓度为6～9g/L时,制备的复合镀层组织细密,显微硬度最高可达7 730MPa,并且耐蚀性也有了较大的提高。     

磁控溅射功率对玻璃基DLC薄膜的结构和硬度的影响

用直流-射频磁控溅射镀膜工艺,在不同的溅射功率条件下,制备了玻璃/SiC/DLC(diamond-like carbon)薄膜.通过X射线衍射仪(XRD)、共焦显微拉曼光谱仪(Raman)、场发射扫描电子显微镜(SEM)、纳米显微硬度仪,研究了DLC薄膜的组织结构、物相组成、表面形貌、维氏硬度.结果表明,随着功率的增大,ID/IG值先增大后减小,薄膜硬度呈现先增大后减小的趋势;当溅射功率为200 W时,ID/IG值为0.56,镀膜玻璃的硬度值最大(830 HV),相比未镀膜的玻璃基片,硬度值增加了23.88％.     

Design and Nanofabrication of Superconductor Ceramic Strands and Customized Leads

We made possible an engineering application of the 18-year-old Nobel Prize-winning discovery of High Temperature Superconductor (HTS) ceramic particles. Guided by certain theories of physics and nano-science, we created the ceramic-silicone nanofabrication method where a silicone additive controls both the nanostructural evolution of the magnetically oriented HTS ceramic nano-grains by a 3D polymeric matrix scaffold and thermally induced nano-phase transformation. These result in the sintered granular superconductor ceramic composite material with the desirable superconducting nano-phase composition and 3D nanostructure including vortex-pinning network. The prototype HTS samples were nanofabricated in the form of adhesion substrate coated strands or surfaces or variously shaped bulk leads.     

纳米科学技术在高分子材料领域的现状

综述了纳米科技在高分子领域的作用，介绍了纳米材料科学和高分子材料科学相交叉的领域的科学进展，简述了高分子纳米复合材料、纳米颗粒的高分子化处理和高分子的纳米尺度的研究。     

Synthesis of stable ACC using mesoporous silica gel as a support

Stable amorphous calcium carbonate supported by mesoporous silica gel was successfully synthesized. The silica gel support is prepared through the hydrolytic polycondensation of ethyl silicate under suitable conditions. Laser scanning confocal microscopy (LSCM) observations reveal that the morphology of the products is branched with cruciform-like and flower-like structure. Raman spectroscopic analysis and scanning electron microscopy (SEM) observation of the products confirm the combination of stable amorphous calcium carbonate (ACC) nanoparticles and mesoporous silica gel. A possible growth mechanism for the branched structure has been proposed. Results indicate potential application of this work to ACC storage, crystal engineering, biomimetic synthesis, etc.     

Imaging of conductive filler networks in heterogeneous materials by scanning Kelvin microscopy

This article reports a novel application of scanning Kelvin microscopy for exclusively revealing the distribution of a percolated conductive filler network in heterogeneous materials. The materials under investigation are carbon black and carbon nanotube‐filled epoxies with a highly inhomogeneous conductivity distribution due to their fabrication. The Kelvin method is demonstrated to be especially suitable for resolving the resistive particle network in these kinds of composite materials with sample resistance levels in the megaohm range. Transmission optical microscopy reveals matches between the scanning Kelvin images and the sample morphologies, whereas the percolating backbone cannot be distinguished in the optical micrographs. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3381–3386, 2001     

High-resolution Kelvin probe microscopy in corrosion science: Scanning Kelvin probe force microscopy (SKPFM) versus classical scanning Kelvin probe (SKP)

With the introduction of a Kelvin probe mode to atomic force microscopy, the so called scanning Kelvin probe force microscopy (SKPFM), the Kelvin probe technique finds application in a steadily increasing number of different fields, from corrosion science to microelectronics and biosciences. For many of these applications, high resolution is required as the relevant information lies in the sub-microscopic distribution of work functions or potentials, which explains the increasing interest in SKPFM. However, compared to the standard scanning Kelvin probe (SKP) technique SKPFM is prone to much more artefacts, which are often not taken into account in the interpretation of the results, as is also the case with the real physical nature of the measured data. A critical discussion of possible artefacts and on the interpretation of the data is presented in this paper, with the main focus on application in corrosion science.     

Atomically-Resolved Investigations of Surface Reaction Chemistry by Scanning Tunneling Microscopy

Research by our group aimed at studying the chemistry of surfaces with atomic-resolution scanning tunneling microscopy is reviewed. Three areas of application are discussed: semiconductor surface chemistry, adsorption processes at metals, and in situ studies of dissolution and oxidation-reduction chemistry of minerals.     

Novel composite polymer electrolyte comprising poly(ethylene oxide) and triblock copolymer/mesostructured silica hybrid used for lithium polymer battery

Ordered mesoporous materials, due to its potential applications in catalysis, separation technologies, and nano-science have attracted much attention in the past few years. In this work, a novel PEO-based composite polymer electrolyte by using organic-inorganic hybrid EO₂₀PO₇₀EO₂₀ @ mesoporous silica (P123 @ SBA-15) as the filler has been developed. The interactions between P123 @ SBA-15 hybrid and PEO chains are studied by X-ray diffraction (XRD), differential scanning calorimeter (DSC), and FT-IR techniques. The effects of P123 @ SBA-15 on the electrochemical properties of the PEO-based electrolyte, such as ionic conductivity, lithium ion transference number are studied by electrochemical ac impedance spectroscopy and steady-state current method. The experiment results show that P123 @ SBA-15 can enhance the ionic conductivity and increase the lithium ion transference number of PEO-based electrolyte, which are induced by the special topology structure of P123 in P123 @ SBA-15 hybrid, at the same time. The excellent lithium transport properties and broad electrochemical stability window suggesting that PEO-LiClO₄/P123 @ SBA-15 composite polymer electrolyte can be used as candidate electrolyte materials for lithium polymer batteries.     

Micropatterning from drying micelle solution of diblock copolymers: strap-structure, quadrate farmland-structure and biomimetic structure

Micropatterns of strap and farmland structures of polystyrene-block-poly(acrylic acid) (PS-b-PAA) copolymer were obtained by drying the micelle solutions. The drying process of the solution was monitored by dynamic optical microscopy (OM) with a digital video camera. The surface structure of the micelle aggregations was studied by OM, scanning electron microscopy and Alpha-Step 200 profiler system. It is believed that solvent evaporation and micelle migration account for the observed micelle micropatterns. The potential application of the micropatterns is also addressed.     

LLDPE/LDPE/纳米TiO2复合薄膜的性能

采用熔融共混方式在线型低密度聚乙烯(LLDPE)／低密度聚乙烯(LDPE)复合体系中添加纳米TiO2制成LLDPE／LDPE／纳米TiO2复合薄膜。通过偏光显微镜、扫描电子显微镜、差示扫描量热法、紫外一可见光吸收光谱,研究了纳米TiO2填充LLDPE／LDPE复合薄膜的力学和光学性能。结果表明,纳米TiO2在薄膜中呈现出理想的分散水平,平均粒径在100nm以下。纳米TiO2在LLDPE／LDPE复合体系的结晶过程中,可起到明显的诱导成核作用,使球晶尺寸细化且数量增多,但复合体系的结晶度无明显变化。该薄膜的透光性仅轻微下降,可满足透明薄膜的使用要求,同时,表现出良好的紫外线吸收功能。