超疏水SiO2/PS 薄膜于木材表面的构建

通过溶胶-凝胶法一步合成疏水性且具备独特形貌的二氧化硅粒子,联合聚苯乙烯以滴涂的方式于木材表面仿生合成了稳定性超疏水薄膜。经处理后的木材表面与水的静态接触角为153°,滚动角小于5°。通过扫描电子显微镜照片观察到该复合涂层拥有微米/亚微米的二维等级粗糙结构,该结构协同低表面能物质共同决定超疏水性木材的成功制得。此外,进一步研究了超疏水性木材表面的稳定性和耐久性。结果表明,该超疏水性木材于水、腐蚀性液体(酸液/碱液)、常见有机溶剂中以及一些常见条件下仍保留超疏水特性,为未来木材材料的应用领域扩展提供了有利条件。     

Fabrication of high performance surface enhanced Raman scattering substrates by a solid-state ionics method

Silver nanostructures were prepared by a solid-state ionics method using fast ionic conductor RbAg(4)I(5) films under a direct current electric field (DCEF). The surface morphology of the silver nanostructures grown under different constant current fields was characterized by scanning electron microscopy (SEM). Rhodamine 6G (R6G) aqueous solutions were used as probe molecules to detect the Raman enhancement performance of the silver nanostructure substrates. The effect of external electric field current intensity on the surface morphology of the silver nanostructures during the preparation was studied in detail. The enhancement effect of the silver nanostructure surface enhanced Raman scattering (SERS) substrates with different surface morphologies toward R6G was determined. We found that disordered silver nanowires (DSNW), ordered silver nanowires (OSNW), densely arranged silver nanobamboo arrays (SNBA) and compactly arranged silver nanobud clusters (SNBC) were respectively obtained when the constant current intensity was 3?μA, 5?μA, 8?μA and 12?μA under the same vacuum evaporation plating conditions. The limiting concentrations of R6G for these SERS substrates were found to be 10(-7)?mol?l(-1), 10(-13)?mol?l(-1), 10(-13)?mol?l(-1) and 10(-16)?mol?l(-1), respectively.     

Fabrication of surface plasmon resonators by nanoskiving single-crystalline gold microplates

This paper demonstrates the sectioning of chemically synthesized, single-crystalline microplates of gold with an ultramicrotome (nanoskiving) to produce single-crystalline nanowires; these nanowires act as low-loss surface plasmon resonators. This method produces collinearly aligned nanostructures with small, regular changes in dimension with each consecutive cross-section: a single microplate thus can produce a number of "quasi-copies" (delicately modulated variations) of a nanowire. The diamond knife cuts cleanly through microplates 35 mum in diameter and 100 nm thick without bending the resulting nanowire and cuts through the sharp edges of a crystal without deformation to generate nanoscale tips. This paper compares the influence of sharp tips and blunt tips on the resonator modes in these nanowires.     

海藻酸钠/SiO2共价交联杂化水凝胶的制备与性能表征

利用海藻酸钠水凝胶上的羧基与硅烷偶联剂γ-氨丙基三乙氧基硅烷上的氨基在常温下反应生成酰胺键而交联,同时硅烷中的乙氧基发生水解缩聚反应得到了有机高分子和无机材料之间以共价键结合的杂化水凝胶;用FTIR、SEM对产物进行了表征,并探讨了杂化水凝胶的溶胀率、剪切模量、网链平均分子量与其结构之间的关系.结果表明,杂化材料中有机无机两相相容性良好,杂化材料的密度、溶涨率及其力学性能可以通过控制无机有机的比例加以控制.     

Fabrication of freestanding SiO2-TiO2 composite by a facile one pot method

A freestanding SiO₂–TiO₂ monolith with bicontinuous structure was prepared via a one pot sol-gel reaction. This monolith was fully characterized by using field emission scanning electron microscopy (FE-SEM), nitrogen adsorption and X-Ray diffraction (XRD). Synthesized SiO₂–TiO₂ monolith possesses great mechanical strength and interconnected macropores (throughpores, textural pores) on the micrometer scale as well as skeleton pores in nanoscale, and also possesses an anatase TiO₂ crystalline structure. Photo-catalytic breakdown of aqueous methylene blue (MB) with UV light was chosen to evaluate photocatalytic efficacy of the SiO₂–TiO₂ catalyst. These photodegradation activities indicated that MB decomposed completely within 180 min and the SiO₂-TiO₂ catalyst was readily separated from the reaction system and easily regenerated. Moreover, the photocatalytic activity of the monolithic catalyst remained unchanged after four catalytic cycles and the morphology was still intact.     

Fabrication of a surface plasmon resonance biosensor based on gold nanoparticles chemisorbed onto a 1,10-decanedithiol self-assembled monolayer

We have investigated the fabrication of surface plasmon resonance (SPR) biosensors using self-assembled monolayers (SAMs) and adsorbed gold nanoparticles. The SAM of 1,10-decanedithiol was first fabricated onto a gold substrate. Gold nanoparticles were then chemisorbed onto the SAM surface by bonding with the terminal thiol groups, forming a sensor that can be used to immobilize proteins. Bovine serum albumin (BSA) was used as a test protein in this study. Several spectroscopic and microscopic techniques were used to investigate both the SAM and the chemisorption of gold nanoparticles at the SAM surface. Our results confirm the covalent bonding of the gold nanoparticles onto the SAM. Surface plasmon resonance (SPR) was used to study both the adsorption of BSA to the SAM surface and to the gold nanoparticle-coated SAM. For SAM surfaces with adsorbed gold nanoparticles a larger SPR response to BSA than to the sensors with a bare SAM is observed.     

Effect of SiO2 substrate on the irradiation-assisted manipulation of supported graphene: a molecular dynamics study

The irradiation effects in graphene supported by SiO(2) substrate including defect production and implantation efficiency are investigated using the molecular dynamics (MD) method with empirical potentials. We show that the irradiation damage in supported graphene comes from two aspects: the direct damage induced by the incident ions and the indirect damage resulting from backscattered particles and sputtered atoms from the substrate. In contrast with the damage in suspended graphene, we find that the indirect damage is dominant in supported graphene at high energies. As a result, enhanced irradiation damage in supported graphene is observed when the incident energy is above 5?keV for Ar and 3?keV for Si. The direct damage probability at all energies, even the total damage probability at low energies, in supported graphene is always much lower than that in suspended graphene because of the higher threshold displacement energy of carbon atoms. In addition, we demonstrate the striking finding that it is possible to dope graphene with sputtered atoms from the substrate and the implantation probability is considerable at optimal energies. Our results indicate that the substrate is an important factor in the process of ion-irradiation-assisted engineering of the properties of graphene.     

膜厚可控SiO2光子晶体的制备与研究

在相同SiO2悬浮液浓度下,采用改进的双基片垂直沉积法成功制备了不同膜厚的SiO2光子晶体薄膜。研究发现,通过调节两基片间夹层厚度可以很好地控制样品薄膜厚度,不同厚度SiO2光子晶体的表面形貌也有一定的变化。     

pH-Dependent gold nanoparticle self-organization on functionalized Si/SiO2 surfaces

The self-organization of citrate- and acrylate-stabilized gold nanoparticles onto SiO₂/hydroxyl-, amino- and nitro-terminated surfaces was investigated as a function of pH. Bare clean Si/SiO₂ substrates were used as the SiO₂/hydroxyl-terminated surfaces and self-assembled monolayers (SAM) of (3-aminopropyl)trimethoxysilane (APTMS) and 3-(4-nitrophenoxy)-propyltrimethoxysilane (NPPTMS) on Si/SiO₂ were employed as the amino- and nitro-terminated surfaces, respectively. All the surfaces were fully characterized by contact angle, atomic force microscopy (AFM), ellipsometry and X-ray photoelectron spectroscopy (XPS). Citrate- and acrylate-stabilized gold nanoparticle stability was also investigated as a function of pH by UV–visible absorption spectroscopy and Z-potentiometry. The gold nanoparticle surface coverage of the substrates was independently estimated by AFM and XPS. The results show that colloid deposition on bare SiO₂/OH surfaces and on NPPTMS monolayers is negligible with the exception of acrylate-stabilized gold nanoparticles which were found to be immobilized on nitro-terminated surfaces at pH lower than 3.5. Nevertheless, APTMS monolayers interact strongly with citrate- and acrylate-stabilized gold nanoparticles exhibiting a dependence of the surface coverage from the pH of the colloidal solution.     

纳米SiO2表面改性及其分散性能研究

采用过氧化氢溶液对纳米二氧化硅(SiO2)粉体进行表面预处理;以γ-(甲基丙烯酰氧)丙基三甲氧基硅烷为改性剂,在水相一油相混合溶液中,对预处理后的纳米SiO2粉体进行表面改性.对改性前后的纳米SiO2粉体采用傅立叶变换红外光谱、紫外一可见光光谱仪、粒径分析等方法进行表征与检测.结果表明:过氧化氢能有效防止纳米Sio2粉体团聚,表面改性后纳米SiO2粉体能均匀分散到有机溶剂中.     

Structural and surface propperties of Ni-Cu nanoparticles supported on SiO2

Nickel (1%) and nickel (1%)-copper (0.2–0.75%) metal phases supported on silica have been prepared by aqueous hydrazine reduction of nickel acetate at 70°C. They were characterized by XRD, TEM, H₂-adsorption and TPD. The obtained results show that nickel is in a whisker-like shape or as a film of low density for the Ni/SiO₂ and Ni-Cu/SiO₂ systems respectively. The mean particle size is lower than 2 nm. Copper is in the shape of bigger facetted particles in the mono or bimetallic systems with a mean particle size of about 25 nm. The nickel phase dispersion, as determined by H₂-adsorption, decreased in the presence of copper, as probably a result of Ni-Cu interactions. All the solids were found to be good hydrogen reservoir through the formation of H-spiltover species. The amounts of hydrogen stored changed with the copper content due to changes in the Ni-Cu interactions.     

氟化聚乙烯醇/SiO_2超疏水薄膜的制备及性能

以亲水性高分子聚乙烯醇(PVA)为基体,二氧化硅(SiO_2)纳米颗粒为无机填料,旋涂在玻璃表面后的PVA/SiO_2再经十七氟癸基三甲氧基硅烷(C_(13)H_(13)F_(17)O_3Si,FAS)修饰,制备了具有超疏水性能的PVA/SiO_2-FAS薄膜。考察了PVA与SiO_2复合的比例及FAS修饰对膜疏水性的影响。用傅里叶变换红外光谱、X射线能谱和扫描电子显微镜分别对超疏水表面进行了结构分析和形貌表征,用接触角测量仪观察了水滴在膜表面的润湿性。结果显示,当PVA/SiO_2体积比为1∶5时,氟化PVA/SiO_2膜表面具有较好的超疏水功能,静态接触角可达151.24°,滚动角约为4°。这主要是膜表面含有低表面能氟原子及具有纳米粗糙结构共同作用的结果。     

静电纺丝法制备超疏水氟硅改性纳米SiO_2/PET共混膜

利用1H,1H,2H,2H-全氟辛基三氯硅烷对SiO_2纳米粒子进行表面改性,制备得到氟硅改性SiO_2纳米粒子(M-SiO_2),并将其与聚对苯二甲酸乙二酯(PET)共混后溶于六氟异丙醇(HFIP)溶剂中进行静电纺丝。采用接触角测量仪、扫描电镜和X射线光电子能谱研究了M-SiO_2/PET电纺膜的疏水性能、表面形貌以及化学组成。结果表明,静电纺丝法制备的M-SiO_2/PET共混电纺膜对水的接触角可高达155.2°,并且对水的滞后角仅为3.4°,即具有超疏水性能。     

SiO2平面光波导工艺中的反应离子刻蚀研究

利用反应离子刻蚀工艺实现硅基SiO2平面光波导的刻蚀,研究了不同刻蚀条件对刻蚀速率、刻蚀选择比、刻蚀侧壁光洁度等刻蚀结果的影响,并首次研究了分别以无定形硅与多晶硅作为SiO2波导刻蚀掩膜对刻蚀垂直度的影响.利用改进的SiO2反应离子刻蚀工艺,得到了传输损耗极低的SiO2光波导.     

Fabrication of solid-state nanopores with single-nanometre precision

Single nanometre-sized pores (nanopores) embedded in an insulating membrane are an exciting new class of nanosensors for rapid electrical detection and characterization of biomolecules. Notable examples include alpha-hemolysin protein nanopores in lipid membranes and solid-state nanopores in Si3N4. Here we report a new technique for fabricating silicon oxide nanopores with single-nanometre precision and direct visual feedback, using state-of-the-art silicon technology and transmission electron microscopy. First, a pore of 20 nm is opened in a silicon membrane by using electron-beam lithography and anisotropic etching. After thermal oxidation, the pore can be reduced to a single-nanometre when it is exposed to a high-energy electron beam. This fluidizes the silicon oxide leading to a shrinking of the small hole due to surface tension. When the electron beam is switched off, the material quenches and retains its shape. This technique dramatically increases the level of control in the fabrication of a wide range of nanodevices.     

Fabrication of nickel nanocontacts using nanostencils and electron beam assisted SiO2 deposition

Nickel nanocontacts for studying ballistic magnetoresistance have been fabricated by sputtering through FIB prepared nanostencil masks and by using electron beam assisted deposition of SiO2 to reduce the size of FIB milled pores through silicon nitride membranes. These two methods are discussed in terms of the nanocontact sizes, fabrication, and yield. The smallest size of the nanocontacts prepared using the nanostencil method was 40 nm and by the filling method was 1-2 nm. The maximum magnetoresistance measured was 1% and no evidence of a large ballistic magnetoresistance was observed.     

Properties of sensors based on shear-horizontal surface acoustic waves in LiTaO3/SiO2 and quartz/SiO2 structures

Acoustic wave devices based on waveguide modes with shear-horizontal polarization, i.e., Love modes, are very promising for sensor application, especially in liquid environments. They can be used for the determination of liquid density and viscosity as well as for chemical sensors. Up to now, several systems have been reported based on standard ST quartz. Those devices lack temperature stability, which is essential for field application. Thus, temperature-compensated systems based on different Y-rotated quartz and lithium tantalate (LiTaO3) plates with SiO2 guiding layers have been investigated. Temperature behavior as well as relevant acoustic properties were considered. Furthermore, experimentally determined data for device sensitivity are compared with theoretical predictions from numerical calculations.