C60—聚苯乙烯LB膜摩擦学性能的初步研究

介绍了Ｃ６０－聚苯乙烯（Ｃ６０－Ｐｓｔ）ＬＢ膜的部分研究结果：合成方法、ＬＢ膜制备、用原子力／摩擦力显微镜测试的Ｃ６０－聚苯乙烯ＬＢ膜的表面微观形貌及轻载荷下的摩擦力等微观摩擦学性能。     

Characterisation and optical vapour sensing properties of PMMA thin films

The present article reports on the characterisation of spin coated thin films of poly (methyl methacrylate) (PMMA) for their use in organic vapour sensing application. Thin film properties of PMMA are studied by UV–visible spectroscopy, atomic force microscopy and surface plasmon resonance (SPR) technique. Results obtained show that homogeneous thin films with thickness in the range between 6 and 15 nm have been successfully prepared when films were spun at speeds between 1000?5000 rpm. Using SPR technique, the sensing properties of the spun films were studied on exposures to several halohydrocarbons including chloroform, dichloromethane and trichloroethylene. Data from measured kinetic response have been used to evaluate the sensitivity of the studied films to the various analyte molecules in terms of normalised response (%) per unit concentration (ppm). The highest PMMA film sensitivity of 0.067 normalised response per ppm was observed for chloroform vapour, for films spun at 1000 rpm. The high film's sensitivity to chloroform vapour was ascribed mainly to its solubility parameter and molar volume values. Effect of film thickness on the vapour sensing properties is also discussed.     

聚乙二醇-碳纳米管(PEG-CNTs)共聚物膜的制备及其微摩擦行为的研究

制备了聚乙二醇接枝碳纳管共聚物(PEG-CNTs)。通过红外光谱(FT-IR)。荧光光谱(FS)和透射电子显微镜(TEM)对共聚物进行了表征。利用旋涂技术以云母为基片制备了共聚物薄膜,采用原子力显微镜／摩擦力显微镜(AFM／FFM)研究了薄膜表面的形貌及微摩擦学行为。复合薄膜内的聚合物组分保证了膜的表面平整,坚硬的碳纳米管组分增强了薄膜的承载能力。     

Third-order nonlinear optical characteristics of bulk film effect on regioregular poly(3-dodecylthiophene) thin films fabricated by the drop-casting method

We report the morphologies and the bulk film effect on regioregular poly(3-dodecylthiophene) [RR-P3DDT] thin films fabricated with different concentrations (0.1, 0.2, 0.4 wt%) by drop-casting method using chloroform as a solvent and fused quartz glass as substrate. The measured thicknesses of the films were 220, 340 and 600 nm. The thin films were characterized by UV–Vis spectra and X-ray diffraction. The surface morphology of the thin film (600 nm) was analyzed using atomic force microscopy. The third order nonlinear susceptibility characteristics of the films were measured using Maker fringes method. These films exhibit efficient THG bulk effect with a maximum χ³ value of 1.41 × 10^?10 esu obtained for 0.4 wt% concentration of RR-P3DDT revealing that this material is potentially suited for fabricating optical limiters.     

Nanodomain development of semifluorinated diblock copolymeric thin films via solvent vapor annealing

The effect of solvent vapor annealing on the morphological change of poly(ethylene oxide)-b-poly(1H,1H dihydrofluorooctyl methacrylate) (PEO-b-PFOMA) micellar thin films has been studied. The time development of the nanodomain structure in PEO(5k)-b-PFOMA(10k) thin films was investigated with the vapor treatment of perfluoroalkanes. The block copolymeric thin film was initially cast from chloroform which is a good solvent for PEO. The as-cast film which has disordered morphology can be changed to ordered cylindrical morphology and at last to highly ordered morphology consisting of PEO spherical domains and PFOMA continuous phase by varying the annealing time.     

Photoluminescence of 2,4,6-tris[4-(phenylethynyl)phenyl]-1,3,5-triazines dispersed in polymer films

Photoluminescence of three types of 1,3,5-triazine derivatives with three kinds of diphenylacetylene side chains was investigated. They showed quantum yields higher than 46% in chloroform, and the Stokes shift (66–114 nm) in chloroform depended on the kind of the diphenylacetylene side chain. In cast films, the three compounds gave a larger Stokes shift of 132–211 nm, suggesting formation of an excimer in the solid. The 1,3,5-triazine derivatives were dispersed in films of polymers such as polystyrene and poly(vinyl acetate), and photoluminescence of the films containing the 1,3,5-triazine derivatives was investigated. Dispersion of the compound in a poly(vinyl acetate) film still gave a rather larger Stokes shift of 128–203 nm. In contrast, dispersion in polystyrene reduced the Stokes shift to about 60 nm, revealing an excellent dispersing effect of polystyrene for the compounds.     

Realization of porous poly(methyl methacrylate) films filled with electrodeposited carbon nanotubes

A deposition process on a conducting surface, in which water acted as the dispersed phase and a mixture of poly(methyl methacrylate) and chloroform as the continuous phase, was applied to prepare poly(methyl methacrylate) films. The influence of relative humidity during the film preparation on the surface morphology was investigated by field emission scanning microscopy. High-humidity preparation conditions lead to porous poly(methyl methacrylate) films. These films were then used as templates to perform the selective deposition into the pores of single-walled carbon nanotubes by an electrophoretic method. The attractive properties of carbon nanotubes combined with the versatile properties of poly(methyl methacrylate) open up new opportunities for these nanocomposites to achieve novel architectures in nanodevices and?microdevices.     

Fourier transform infrared spectroscopy characterization of AlN thin films grown on sacrificial silicon oxide layers via metal organic vapor phase epitaxy

Aluminum nitride (AlN) films were grown using metal organic vapor phase epitaxy techniques on Si (111) substrates patterned with silicon oxide (SiO_x) stripes and the vibrational properties of these films were investigated by Fourier transform infrared (FTIR) techniques. The grown films contained a predominantly wurtzite AlN phase. The AlN film on SiO_x was prone to corrosion when subjected to wet etching in buffered hydrofluoric acid solution thereby changing the material properties of the AlN film on SiO_x. The change in the material properties of the AlN films on SiO_x can be gauged from the decrease in the relative integrated areas under the A1 (TO) and E1 (TO) modes of the AlN film. The analysis shows that FTIR is a viable tool for investigating the material properties of AlN thin film structures with lateral dimensions as low as 100 μm.     

Photoluminescence of 2,4,6-tris[4-(phenylethynyl)phenyl]-1,3,5-triazines dispersed in polymer films

Photoluminescence of three types of 1,3,5-triazine derivatives with three kinds of diphenylacetylene side chains was investigated. They showed quantum yields higher than 46% in chloroform, and the Stokes shift (66–114 nm) in chloroform depended on the kind of the diphenylacetylene side chain. In cast films, the three compounds gave a larger Stokes shift of 132–211 nm, suggesting formation of an excimer in the solid. The 1,3,5-triazine derivatives were dispersed in films of polymers such as polystyrene and poly(vinyl acetate), and photoluminescence of the films containing the 1,3,5-triazine derivatives was investigated. Dispersion of the compound in a poly(vinyl acetate) film still gave a rather larger Stokes shift of 128–203 nm. In contrast, dispersion in polystyrene reduced the Stokes shift to about 60 nm, revealing an excellent dispersing effect of polystyrene for the compounds.     

Surface characterization of completely degradable composite scaffolds

The goal of this study was to characterise the surface properties of completely degradable composite, polylactic acid and calcium phosphate glass, scaffolds. The composite scaffolds are made by solvent casting or phase-separation, using chloroform and dioxane as a solvent respectively. The surface properties were measured on composite films which were made using the same procedure as for the three-dimensional (3D) scaffolds without the pore-creating step. The surface morphology, roughness, wettability and protein adsorption capacity of the films was measured before and after sterilisation with ethylene oxide. The results reveal the influence of solvent type, glass weight content and sterilisation on the wettability, surface energy and protein adsorption capacity of the materials. The addition of glass particles increase the hydrophylicity, roughness and protein adsorption capacity of the surface. This effect, however, depends on the extent of the coating of the glass particles by the polymer film, which is much higher for dioxane films than for chloroform films. This information can be used to interpret and understand the biological behaviour of the 3D scaffolds made of this composite materials.     

氟化PVA-SiO2薄膜单面疏水性的研究与表征

目的 研究开发一种具有单面疏水性能的聚乙烯醇薄膜材料作为包装材料。方法 将质量分数为12%、醇解度为88%的PVA溶液与质量分数为5%的纳米SiO2溶液按体积比为1∶1混合并加热搅拌,通过流延干燥的方式制备PVA-SiO2薄膜。然后分别用体积分数为2.5%,5%,7.5%的十七氟癸基三甲氧基硅烷（FAS）-乙醇溶液以浸泡方式修饰薄膜的其中一面,并通过溶解性测试、接触角测试、场发射扫描电子显微镜（FE-SEM）、傅里叶变换衰减全反射红外光谱测试（ATR-FTIR）等方法表征改性结果。结果 结果表明薄膜单面疏水性得到改善,改性后的薄膜在水中的溶解时间增加,且接触角均在120°以上,表明FAS起到了降低表面能的作用;FE-SEM结果显示,Si元素含量对薄膜的疏水性能有着重要影响;ATR-FTIR显示,FAS改性成功将氟原子引入到薄膜表面,且增加了硅原子的数量。其中用质量分数为5%的FAS-乙醇溶液修饰后的薄膜疏水性最好,接触角达到了126.21°。结论 与未改性薄膜相比,经FAS单面疏水改性的PVA-SiO2薄膜疏水性能得到大大提高,拓宽了PVA薄膜材料的应用领域。     

Compositional analysis of electrodeposited bismuth telluride thermoelectric thin films using combined electrochemical quartz crystal microgravimetry--stripping voltammetry

Bismuth telluride (Bi 2Te 3 ) is a benchmark material for thermoelectric power generation and cooling applications. Electrodeposition is a versatile technique for preparing thin films of this material; however, it affords films of variable composition depending on the preparation history. A simple and rapid assay of electrodeposited films, therefore, has both fundamental and practical importance. In this study, a new protocol for the electroanalysis of Bi 2Te 3 thin films is presented by combining the two powerful and complementary techniques of electrochemical quartz crystal microgravimetry (EQCM) and stripping voltammetry. First, any free (and excess) tellurium in the electrodeposited film was reduced to soluble Te ( 2- ) species by scanning to negative potentials in a 0.1 M Na 2SO 4 electrolyte, and the accompanying frequency increase (mass loss) was used to determine the content of free tellurium. The film was again subjected to cathodic stripping in the same medium (to generate Bi (0) and soluble Te (2-) from the Bi 2 Te 3 film component of interest), and the EQCM frequency change was used to determine the content of chemically bound Te in the Bi 2Te 3 thin film and thereby the compound stoichiometry. Finally, the EQCM frequency change during Bi oxidation to Bi (3+) and the difference between total Bi and Bi in Bi 2Te 3 resulted in the assay of free (excess) Bi in the electrodeposited film. Problems associated with the chemical/electrochemical stability of the free Bi species were circumvented by a flow electroanalysis approach. Data are also presented on the sensitivity of electrodeposited Bi 2Te 3 film composition to the electrodeposition potential. This newly developed method can be used for the compositional analysis of other thermoelectric thin-film material candidates in general.     

Effect of chain conformation on micro-mechanical behaviour of MEH–PPV thin film

The morphology, photoluminescent properties and micro-mechanical character of poly[2-methoxy-5-(2′-ethylhexyloxy)-p-phenylene vinylene] (MEH–PPV) thin films prepared from toluene (T film) and chloroform (C film) were studied by transmission electron microscopy (TEM), absorption, photoluminescence spectrophotometry and nanoindentation test. The morphological feature of worm-like entities which appeared in T film was ~10–20 nm in length and 3–5 nm in width. The C film displayed the continuous cotton fibre-shaped morphology. In contrast with C film, the band-edge absorption and maximum emission for T film shifted to the longer wavelength. An analysis from TEM photograph, absorption and photoluminescence spectra indicated that different chain conformation presented in these two kinds of films. The nanoindentation test showed that the elastic modulus and indentation hardness of T film under the same experimental parameter (load: 50–200 μN, loading rate: 20 μN/s and holding time: 20 s) decreased by 33·3 ± 0·3 and 8·9 ± 0·5%, respectively comparing with C film. In addition, critical bending radius of these two films based on the flexible base was also evaluated from the obtained experimental results.     

Instabilities in nanoporous media

Rayleigh instabilities in thin polymer films confined within nanoporous alumina membranes were studied. Thin films of poly(methyl methacrylate) (PMMA) were prepared by filling cylindrical nanopores in an anodic aluminum oxide (AAO) membrane with a PMMA solution in chloroform followed by solvent evaporation. When the PMMA nanotubes were annealed above the glass transition temperature (Tg), undulations in the film thickness were observed that were induced by a Rayleigh instability. The amplitude of the undulations increased with time and eventually bridged across the cylindrical nanopore in the AAO membrane, resulting in the formation of polymer nanorods with periodic encapsulated holes. A similar behavior was observed when PMMA films were confined within carbon nanotubes (CNTs). The Rayleigh instabilities in these confined geometries offer a novel means of controlling and fabricating the polymer nanostructures. These compartmentalized nanorods may have potential applications as delivery devices.     

纳米银-聚合物薄膜的制备及力电性能测试

聚合物基底上纳米银颗粒薄膜的制备工艺相对简单,成本较低,且该薄膜具有成为高敏感性压阻应力/应变传感材料的潜力。本文采用银镜制备法在聚酰亚胺(PI)和聚乙烯(PE)上合成了纳米银颗粒薄膜,系统研究了该薄膜制备工艺、结构特性、材料性能之间的关系。实验考察了材料“浸泡”时间及聚合物材料前处理等因素对材料表面吸附纳米颗粒含量的影响,研究了 “浸泡”时间对纳米银颗粒粒径大小、颗粒含量及分布的影响,并探讨了不同聚合物基体的颗粒特性对薄膜二维导电渗滤,压阻特性及拉伸性能的影响。研究表明,增加“浸泡”时间能够增加纳米银颗粒粒径大小,提高银颗粒的含量及分布均匀性；在相同的制备条件下,PI基底较PE基底对纳米银颗粒具有更加优异的吸附效果；在PI 和PE基底上的纳米银颗粒薄膜均表现出显著的压阻性能,且电阻对应变的敏感性随应变的增大及银颗粒含量的减少而显著提高。     

Effect of silylation on triethoxyfluorosilane xerogel films by means of atmospheric pressure drying

Triethoxyfluorosilane-based (TEFS) xerogel films have been reacted with silylation agents and characterized. TEFS films have been employed because they form robust silica networks and exhibit low dielectric constants. However, these films readily absorb moisture. Employing silylation reactions enhances film hydrophobicity and permits possible introduction of this film as an interlayer dielectric material. Fourier transform infrared spectroscopy was used to verify the presence of methyl groups and extent of silylation in the silica films. Thicknesses and refractive indices of the subject films were determined by ellipsometry studies, and porosity was determined by the refractive indices. Hydrophobicity of the silica films was measured by the sessile-drop goniometric contact angle technique.     

载银纳米纤维素/聚乙烯醇复合膜的制备及性能研究

目的制备一种具有良好力学性能和抑菌性能的新型抗菌聚乙烯醇复合膜。方法通过酸水解微晶纤维素制备纳米纤维素,经高碘酸钠氧化获得醛基纳米纤维素,加入银氨溶液原位合成载银纳米纤维素(Ag-DCNC)。以聚乙烯醇(PVA)为成膜基底,加入Ag-DCNC共混流延制备载银纳米纤维素/聚乙烯醇复合膜。结果 Ag-DCNC体积分数为3%时,复合膜的拉伸强度比纯PVA膜提高了8.8%。Ag-DCNC体积分数为5%的复合膜对大肠杆菌和金黄色葡萄球菌均具有较好的抑菌效果。结论载银纳米纤维素/聚乙烯醇复合膜具有较好的力学强度,对2种细菌均有良好的杀菌效果。该材料不但具有良好的性能,而且合成工艺简单,可以作为一种很有前途的抑菌膜用于包装行业。     

A study of Langmuir-Blodgett thin film for organic vapor detection

In this work, arachidic acid was deposited onto a quartz crystal using a standard Langmuir-Blodgett (LB) thin film deposition procedure. Quartz Crystal Microbalance (QCM) technique was used to monitor the reproducibility of the LB film monolayer and was employed to study the organic vapor sensing properties of chloroform, toluene, benzene, ethyl alcohol and isopropyl alcohol. QCM results show that arachidic acid monolayer was successfully organised and deposited from the water surface onto a quartz crystal substrate. This LB film is found to be highly sensitive and selective to chloroform vapor than other vapors. The response of the sample against chloroform is fast, large and reversible.     

乳清蛋白添加量对交联羧甲基玉米淀粉可食膜阻隔性能的影响

以交联羧甲基玉米淀粉(CCMS)为原料,辅以增强剂、增塑剂、脱泡剂及脱膜剂等,通过流延方法制备了交联羧甲基玉米淀粉/乳清蛋白可食性复合包装膜。实验考察了乳清蛋白粉的添加量对交联羧甲基玉米淀粉可食性膜阻隔性能的影响。结果表明:乳清蛋白添加量为15%(质量分数)时,可食性复合膜的阻隔性最好,其透氧系数为0.312×10-15cm3.cm/(m2.s.Pa),水蒸气透过系数为2.89 g.mm/(m2.d.kPa),吸水稳定性好。     

Investigation into polishing process of CVD diamond films

A new technique used for polishing chemical vapor deposition (CVD) diamond films has been investigated, by which rough polishing of the CVD diamond films can be achieved efficiently. A CVD diamond film is coated with a thin layer of electrically conductive material in advance, and then electro-discharge machining (EDM) is used to machine the coated surface. As a result, peaks on the surface of the diamond film are removed rapidly. During machining, graphitization of diamond enables the EDM process to continue. The single pulse discharge shows that the material of the coated layer evidently affects removal behavior of the CVD diamond films. Compared with the machining of ordinary metal materials, the process of EDM CVD diamond films possesses a quite different characteristic. The removal mechanism of the CVD diamond films is discussed.