Surface modification and characterization of magnesium hydroxide sulfate hydrate nanowhiskers

In order to enhance the compatibility with plastic polymers, magnesium hydroxide sulfate hydrate (MHSH) nanowhiskers were modified through grafting methyl methacrylate (MMA) on the surface of the nanowhiskers by emulsion polymerization. The influences of the reaction time, MMA monomer content, adding speed of monomer and the reaction temperature on the grafting ratio were investigated. Thermogravimetry (TG), Fourier transform infrared (FT-IR) spectroscopy, X-ray powder diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray (EDX) spectroscopy and surface contact angle measurement were used to characterize the effect of surface modification. The results showed that the MHSH nanowhiskers were uniformly coated by polymethyl methacrylate (PMMA), and a well-defined core-shell hybrid structure of MHSH/PMMA was obtained. The surface contact angle of the hybrid whiskers increased to 87.32° from 12.71° and the whiskers surface was changed from hydrophilic to lipophilic.     

Fabrication of triazinedithiol functional polymeric nanofilm by potentiostatic polymerization on aluminum surface

The functional polymeric nanofilm of 6-(N-allyl-1,1,2,2-tetrahydroperfluorodecyl)amino-1,3,5-triazine-2,4-dithiol monosodium (AF17N) was prepared on pure aluminum surface by potentiostatic polymerization at different potentials. The thickness and weight of polymeric nanofilm increased proportionally to electro-polymerization potential following linear equation. The chemical structure of nanofilm was characterized by Fourier transform-infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Adsorption peaks in FT-IR and C1s, N1s, S2p, F1s and Al2p peaks in XPS spectra indicated that the polymeric nanofilm was poly(6-(N-allyl-1,1,2,2-tetrahydroperfluorodecyl)amino-1,3,5-triazine-2,4-disulfide) (PAF17). The morphologies of polymeric nanofilm were also observed by atomic force microscopy (AFM). All the results showed that the optimal electro-polymerization potential and time were 8 V and 20 s, respectively. Uniform and compact nanofilm of PAF17 could be obtained under these conditions. It is expected that this technique will be applied in the preparation of lubricating, dielectric and hydrophobic surface on aluminum substrate.     

铝在氢氧化钠溶液中的腐蚀动力学行为

在高效率转化腔的制备过程中,使用氢氧化钠溶液去除铝芯轴是最关键的步骤之一。为掌握铝在氢氧化钠溶液的腐蚀行为,采用失重法,研究铝在30 ℃条件下,1~5 mol/L的氢氧化钠溶液中的动力学行为;以及在3 mol/L的氢氧化钠溶液中,30~50 ℃条件下的氢氧化钠溶液中的动力学行为。对数据进行拟合和经验公式处理,求出各动力学参数（反应级数,速率常数,表观活化能、指前因子）,并通过X射线衍射仪对其产物进行分析。     

铝在氢氧化钠溶液中的腐蚀动力学行为

在高效率转化腔的制备过程中,使用氢氧化钠溶液去除铝芯轴是最关键的步骤之一。为掌握铝在氢氧化钠溶液的腐蚀行为,采用失重法,研究铝在30 ℃条件下,1~5 mol/L的氢氧化钠溶液中的动力学行为;以及在3 mol/L的氢氧化钠溶液中,30~50 ℃条件下的氢氧化钠溶液中的动力学行为。对数据进行拟合和经验公式处理,求出各动力学参数（反应级数,速率常数,表观活化能、指前因子）,并通过X射线衍射仪对其产物进行分析。     

N+离子注入聚四氟乙烯表面改性研究

在剂量为1×1014—1×1017ions／cm2的范围内，在不同的温度条件下，用 能量为160keV氮离子对PTFE表面进行注入处理，处理后的样品用可见(514．5nm)和傅里叶红 外(1064nm)拉曼(Raman)光谱以及扫描电镜和x射线能谱仪进行检测.实验结果表明低剂量注 入可以增强PTFE晶体结构的取向和有序性；中等剂量时溅射损失效应明显，表面粗糙度加大 ：高剂量注入时微观结构强烈地变化并生成CC双键，导致表面碳化.另外温度对表面改性效 果有很大的影响.刻蚀率和表面的微观结构的变化随着温度的升高而增强.离子注入前，用喷 射技术使样品覆盖一层150nm的金膜，薄膜的黏结性和硬度用划痕和透明胶带测试配合扫描 电镜进行分析.分析结果表明，黏结性在注入剂量为1014ions／cm2时明显增强，这 个结果与表面亲水性测量结果是一致的.但表面硬度只在温度为180℃时才得到了增强. 关键词： 离子注入 聚四氟乙烯 表面改性     

Hydrophobic modification of SiO2 surface by aminosilane derivatives

New aminosilanes with hydrolysable Si-N bond(s) were prepared by the amination of chlorosilanes and used as hydrophobic modifiers of SiO₂ surface. The aminosilanes are rather stable towards hydrolysis in air compared to their chlorosilane analogs. The modified SiO₂ was applied as a gate insulator of an organic thin-film transistor with a vapor-deposited film of pentacene as the active material. The transistor with the aminosilane-modified SiO₂ showed two- to threefold higher hole mobility than the device with bare SiO₂.     

Polypropylene surface modification by entrapment of polypropylene-graft-poly(butyl methacrylate)

Surface modification of polypropylene was carried out by entraping a copolymer of polypropylene grafted poly(butyl methacrylate) into polypropylene. The effects of structure of copolymers, contact die and content of modifiers on their surface enrichment were studied by attenuated total reflection infrared spectroscopy (ATR-FTIR), contact angle measurements and scanning electron microscopy (SEM). The results indicated that PPw-g-PBMA could diffuse preferably onto the surface and effectively increase the hydrophilicity of PP. Lower content and higher surface energy die were in favor of the copolymer to enrich on the PP surface. PPw-g-PBMA with low PBMA contents, short length of PBMA distributed in PP with smaller phase domains and favored its selective enrichment on the surface of PP, especially at lower loadings in blends. The modified material exhibited excellent solvent-resistance.     

Improving wear resistance of pure copper by laser surface modification

With the aim of improving surface strength on copper with the electrical conductivity of the integral bulk retained, laser surface modification on copper was carried out using powder preplacement. The microstructures, hardness, wear resistance and electrical conductivity of the sample was investigated. It was shown that the modified layer of sample had crack-free, fine and homogeneous microstructures. Compared with pure copper, the average hardness of the sample was enhanced by a factor of six (about HV_0.1650), and the wear mass loss was reduced by 4/5, but the electrical conductivity of the integral bulk was only slightly decreased. The improvement of hardness and wear resistance could be attributed to the precipitation hardening of boride and carbide, grain refinement and solid solution strengthening in the layer.     

In situ surface modification of natural fiber by conducting polyaniline

Newly modified biofibers made up of kenaf fibers (KF) and conducting polyaniline (PANI) were successfully prepared via in situ polymerization. Several characterization methods were done to elucidate the interaction between the KF surfaces and the in situ polymerized PANI. The PANI coated KF (KF/PANI) achieved new electronic properties, without sacrificing its mechanical properties and natural fiber characteristic. Initial mercerization on the KF yielded better PANI coated fibers compared to the untreated KF. Fiber bundle tensile test on the untreated KF/PANI revealed a drop in the unit break of about 48% compared to the untreated neat KF. Meanwhile, the mercerized KF/PANI showed reduction of about 17% compared to the uncoated mercerized KF. The mercerized KF/PANI exhibits polaronic transitions, existence of favorable IR peaks and Raman scattering, enhanced DC conductivity, and better morphological characteristic as a result of the in situ PANI coating. Such electronically modified natural fibers could be suitable as green conducting fillers in composites to replace other synthetic fibers.     

GaAs surface passivation by plasma-enhanced atomic-layer-deposited aluminum nitride

A low-temperature passivation method for GaAs surfaces is investigated. Ultrathin AlN layers are deposited by plasma-enhanced atomic-layer-deposition at 200 ° C on top of near-surface InGaAs/GaAs quantum well structures. A significant passivation effect is seen as shown by up to 30 times higher photoluminescence intensity and up to seven times longer lifetime compared to uncoated reference samples. The improved optical properties are accompanied by a redshift of the quantum well photoluminescence peak likely caused by a combination of the nitridation of the GaAs capping layer and a surface coupling effect.     

Surface modification of magnesium aluminum hydroxide nanoparticles with poly(methyl methacrylate) via one-pot in situ polymerization

Hydrophobic magnesium aluminum hydroxide composite particles (PMMA-MAH) were obtained by means of grafting poly(methyl methacrylate) (PMMA) onto the surface of magnesium aluminum hydroxide(MAH) nanoparticles after a novel type of phosphate coupling agent (DN-27) modification. The introduction of functional double bonds was firstly conducted on the surface of nanoparticles by DN-27 modification, followed by one-pot in situ polymerization on the particles surface using methyl methacrylate (MMA) as monomer, azoisobutyronitrile (AIBN) as initiator and sodium dodecyl sulfate (SDS) as stabilizer to graft PMMA on the surface of DN-27-modified MAH particles. The obtained composite particles were characterized by field-emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD). The results show that the organic macromolecule PMMA could be successfully grafted on the surface of DN-27-modified MAH nanoparticles and the thermal stability of the PMMA-MAH composite particles had been improved. Compared with unmodified blank MAH sample, the product obtained with this method possesses better hydrophobic properties such as a higher water contact angle of 108° and a well dispersion.     

表面修饰基团对金纳米颗粒非线性光学效应的影响研究

采用两相法分别制备一级硫醇修饰和二级十六烷基三甲基溴化铵(CTAB) 修饰的金纳米颗粒,通过透射电子显微镜和紫外-可见吸收光谱表征了其结构和线性光学性质. 采用开孔Z扫描技术,研究表面修饰对金纳米颗粒在532 nm波长激光作用下的非线性光学效应及光限幅性能的影响行为.结果表明,二级CTAB的修饰增强了颗粒在激光照射下的局域场作用, 并提高了热电子对非线性光学效应的贡献程度,从而有效地提高了金纳米颗粒的光限幅性能.     

臭氧化法表面改性聚苯乙烯薄膜

为增强聚苯乙烯(PS)与聚乙烯醇(PVA)之间的结合力,进而提高PS-VA双层空心微球存活率。利用臭氧化改性法在酸性介质中对聚苯乙烯薄膜进行表面改性,用红外光谱对处理后的表面进行了半定量的分析。结果表明：改性过后聚苯乙烯表面产生羟基、羰基等极性基团;接触角测试证明,处理后的表面由憎水变为亲水,并通过纳米压痕划痕法得到了处理前后PS与PVA薄膜之间的相互作用强度,臭氧化改性后PS与PVA膜间作用强度增大了40%。     

High-power laser beam shaping by inseparable two-dimensional binary-phase gratings for surface modification of stamping dies

For surface modification of stamping dies, an inseparable two-dimensional binary-phase gratings is introduced to implement the wavefront transformation of high-power laser beams. The design and fabrication of the gratings are described in detail. Two-dimensional even sampling encoding scheme is adopted to overcome the limitations of conventional Dammann grating in the design of two-dimensional output patterns. High diffractive efficiency (>70%) can be achieved through the transformation of the Gaussian laser beam into several kinds of two-dimensional arrays in focal plan. The application of the binary-phase gratings in the laser surface modification of ductile iron is investigated, and the results show that the hardness and the wear resistance of the sample surface were improved significantly by using the binary-phase gratings.     

臭氧化法表面改性聚苯乙烯薄膜

 为增强聚苯乙烯(PS)与聚乙烯醇(PVA)之间的结合力,进而提高PS-VA双层空心微球存活率。利用臭氧化改性法在酸性介质中对聚苯乙烯薄膜进行表面改性,用红外光谱对处理后的表面进行了半定量的分析。结果表明：改性过后聚苯乙烯表面产生羟基、羰基等极性基团;接触角测试证明,处理后的表面由憎水变为亲水,并通过纳米压痕划痕法得到了处理前后PS与PVA薄膜之间的相互作用强度,臭氧化改性后PS与PVA膜间作用强度增大了40%。     

RB-SiC表面改性Si涂层的制备与性能

为了获得高质量光学表面的碳化硅反射镜,利用射频磁控溅射方法,在直径70 mm的RB-SiC基片上沉积了厚约100 μm的Si改性涂层,对改性层进行超光滑加工,并对改性层的表面形貌及性能进行了测试。ZYGO表面粗糙度仪测试结果表明,抛光后Si改性涂层表面粗糙度均方根值达到了0.496 nm;X射线衍射仪测试显示,制备Si改性涂层为多晶结构;使用拉力机做附着力测试,结果表明膜基附着力大于10.7 MPa。证明采用磁控溅射技术制备的Si改性涂层均匀、致密、附着力好,能够满足RB-SiC材料表面改性要求。     

High-performance n-channel organic thin-film transistors based on the dual effects of heterojunction and surface modification

This paper presents two n-channel organic heterojunction transistors with modified insulator by using hexadecafluorophthalocyaninatocopper (F₁₆CuPc)/copper phthalocyanine (CuPc) and F₁₆CuPc/pentacene as the active layers. Compared with a single-layer device, it reports that an improved field-effect mobility and a 6-fold higher drain current are observed. The highest mobility of 0.081~cm²/(V.s) was obtained from F₁₆CuPc/CuPc heterojunction devices. This result is attributed to the dual effects of the organic heterojunction and interface modification. Furthermore, for two heterojunction devices, the performance of the F₁₆CuPc/CuPc-based transistor is better than that of F₁₆CuPc/pentacene. This is attributed to the morphologic match of two organic components.     

Preparation and surface modification of silicon nanowires under normal conditions

Preparation and surface modification of silicon nanowires (SiNWs) grown by the metal catalyzed solution method under normal conditions (room temperature, 1 atm) had been studied in this paper. Firstly, SiNWs using a simple solution method via electroless metal deposition (EMD) of silver under room temperature, standard pressure had been prepared. The influence of the growth parameters such as solution concentration, etching time on the SiNWs formation had been studied. Secondly, the surface modification of SiNWs with platinum and copper had been investigated. The results indicated that the SiNWs modified with Pt and Cu showed different surface morphologies. Pt modification on SiNWs presented in the form of nanoparticles, whereas Cu modification in the form of membrane. Therefore, the Pt modified SiNWs have more vast surface-to-bulk ratio than the unmodified ones, and SiNWs modified with copper nanoparticles will lead to the smaller surface-to-bulk ratio. So the platinum-modified SiNWs have a promising application in sensors’ field.     

RB-SiC表面改性Si涂层的制备与性能

 为了获得高质量光学表面的碳化硅反射镜,利用射频磁控溅射方法,在直径70 mm的RB-SiC基片上沉积了厚约100 μm的Si改性涂层,对改性层进行超光滑加工,并对改性层的表面形貌及性能进行了测试。ZYGO表面粗糙度仪测试结果表明,抛光后Si改性涂层表面粗糙度均方根值达到了0.496 nm;X射线衍射仪测试显示,制备Si改性涂层为多晶结构;使用拉力机做附着力测试,结果表明膜基附着力大于10.7 MPa。证明采用磁控溅射技术制备的Si改性涂层均匀、致密、附着力好,能够满足RB-SiC材料表面改性要求。     

Mechanism of formation of highly conductive layer on ZnO crystal surface

The mechanism of formation of a thin highly conductive layer, which is known to be present on ZnO surface, has been proposed. This process has been assumed to consist in accumulation of mobile shallow donors at crystal surface due to their drift in band-bending electric field caused by adsorbed oxygen. Experimental results that confirm this mechanism have been obtained.