Surface-initiated ATRP of 2-(methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate on Phynox

Phynox is of high interest for technological applications due to its high corrosion resistance, mechanical properties and biocompatibility. In combination with these remarkable characteristics, some Phynox applications require specific surface properties that can be imparted with suitable surface functionalizations of the oxide layer. The present work aims at studying the surface-initiated atom transfer radical polymerization (ATRP) of 2-(methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate (MPC) on Phynox substrates, using grafted 11-(2-bromoisobutyrate)-undecyl-1-phosphonic acid as initiator. The ability of the initiator to bind Phynox substrates and act as an initiator for ATRP of MPC is investigated. It appears that ATRP polymerization of MPC on modified Phynox substrates already takes place in aqueous media at room temperature, but the yield at 90 °C is superior.     

Surface analysis of inhibitor films formed by imidazolines and amides on mild steel in an acidic environment

Imidazolines and amidic precursors were synthesized with good yields through an optimized process. These compounds were evaluated as corrosion inhibitors in an aqueous solution of 1.0 M HCl by gravimetric and polarization techniques. AISI 1018 carbon steel displayed a corrosion rate dependent on the molecular structure and concentration of inhibitor in the testing environment. Adsorption of inhibitors was found to follow the Langmuir's isotherm, this concept together with Gibbs’ free energy provided the basis to arrange corrosion inhibitors according to efficiency and stability. The surface analysis by AFM displayed that the damage on the metallic surface was considerably reduced in the presence of certain inhibitors. XPS determined the presence of a layer of inhibitor on the metal surface with protective properties.     

Polysulfobetaine films prepared by electrografting technique for reduction of biofouling on electroconductive surfaces

The sulfobetaine films were prepared on stainless steel and golden surfaces. In the first step, the poly(2-(dimethylamino)ethyl methacrylate) film was created by employing the electrografting polymerization technique. In the second step, this film was modified to polysulfobetaine, i.e. the polymer film bearing the zwitterionic groups. The presence of the electrografted film and its modification were determined by contact angle measurements, infrared spectroscopy in reflectance mode and X-ray photoelectron spectroscopy. The prepared films were homogeneous with the thickness from about 5 to 26 nm as determined by X-ray photoelectron spectroscopy. The atomic force microscopy measurements showed the increase of surface roughness upon the surface coating. In vitro tests using adherent RAT-2 fibroblast cells and fluorescently labelled bovine serum albumin proteins showed that prepared polysulfobetaine films can be used in applications requiring the resistance against cell attachment and biofouling.     

Surface cleaning procedures for thin films of indium gallium nitride grown on sapphire

Surface preparation procedures for indium gallium nitride (InGaN) thin films were analyzed for their effectiveness for carbon and oxide removal as well as for the resulting surface roughness. Aqua regia (3:1 mixture of concentrated hydrochloric acid and concentrated nitric acid, AR), hydrofluoric acid (HF), hydrochloric acid (HCl), piranha solution (1:1 mixture of sulfuric acid and 30% H₂O₂) and 1:9 ammonium sulfide:tert-butanol were all used along with high temperature anneals to remove surface contamination. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were utilized to study the extent of surface contamination and surface roughness, respectively. The ammonium sulfide treatment provided the best overall removal of oxygen and carbon. Annealing over 700 °C after a treatment showed an even further improvement in surface contamination removal. The piranha treatment resulted in the lowest residual carbon, while the ammonium sulfide treatment leads to the lowest residual oxygen. AFM data showed that all the treatments decreased the surface roughness (with respect to as-grown specimens) with HCl, HF, (NH₄)₂S and RCA procedures giving the best RMS values (∼0.5-0.8 nm).     

Chemical and structural analysis of low-temperature excimer-laser annealing in indium-tin oxide sol-gel films

We investigated the influence of excimer-laser annealing (ELA) on the electrical, chemical, and structural properties of indium–tin oxide (ITO) films prepared by a solution process. The ITO film was prepared by the sol-gel method and annealed by excimer-laser pulses with an energy density up to 240?mJ/cm². Hall measurements showed that the ELA substantially enhanced the electrical properties of the ITO films, including their resistivity, carrier density, and mobility, as increasing the laser energy density. In-depth x-ray photoelectron spectroscopy analysis of the chemical states in the film surface showed that the ELA reduced carbon species and promoted both an oxidation and crystallization. These changes were consistent with results of x-ray diffraction and transmission electron microscopy measurements, where expansions in the microcrystal growth were observed for higher laser energy density. We comprehensively understand that the chemical rearrangement and concomitant crystallization are the main factors for achieving the electrical properties during the ELA. These results suggest the potential of the ELA-treated sol-gel films for providing high-quality ITO films at low temperatures toward the flexible device applications.     

Surface analysis for catalyst layer (PT/PTFE/C) and diffusion layer (PTFE/C) for proton exchange membrane fuel cells systems (PEMFCs)

X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) studies have been used to analyze the surface of diffusion layer (PTFE/C) and catalyst layer (Pt/C/PTFE) of electrode. Detail analysis of carbon C_1s peak showed that the carbon was of the form of C, C-O, CO, CF, CF₂ and CF₃ with CF₂ is more dominated on the surface compared to CF and CF₃. The oxygen O_1s photoelectron peak showed that the oxygen was of the form of CO and C-O. The platinum was of the form of Pt⁰ with some Pt oxidized to PtO. The scanning electron microscopy was used to observe the dispersion of Teflon in the diffusion layer, the distribution of platinum in the catalyst layer loaded with 0.38 mg Pt/cm² and also the cross section of the membrane electrode assembly. The prepared electrode delivers a superior performance compared with the commercial electrode (E-TEK). The difference in performance between the two electrodes is due to the good localization of the platinum particles.     

Surface analysis for LiBq4 growing on ITO and CuPc film using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS)

We have investigated the morphology and surface electron states of LiBq₄ deposited on ITO and CuPc/ITO, using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The AFM observations indicate that LiBq₄ can form a much more uniform film on CuPc than that on ITO. Furthermore, X-ray photoelectron spectroscopy (XPS) is utilized to further demonstrate the AFM results. From the analysis of XPS, we found that LiBq₄ molecules have poor thermal stability, they are seriously oxidized during depositing; but when a CuPc layer is inserted between LiBq₄ and ITO film, the oxidation and surface contamination of LiBq₄ are significantly reduced. It is then concluded that the introduction of a CuPc buffer layer under the LiBq₄ film can improve the film quality of LiBq₄.The XPS results also testified the fact that no coordination bonds between N atoms and B atoms are formed in LiBq₄ molecules, which make LiBq₄ to be potential blue organic light-emitting material.     

Li掺杂8-羟基喹啉铝的密度泛函理论研究

采用密度泛函理论研究了Li原子掺杂8-羟基喹啉铝(Alq₃)分子的几何构型、 前线分子轨道及电子转移特性. 研究结果表明, Li原子掺杂Alq₃后, Li原子与Alq₃的O, N原子键合, 形成电子转移复合物. Li原子将部分电子转移到Alq₃的吡啶环上, 在Alq₃的带隙内形成施主能级, 这种n型掺杂结构有效地提高了电子的传输效率; 但过多的Li原子的掺杂会使Alq₃分解, 从而减弱其电子传输能力. 为使Alq₃的电子传输能力达到最高, Li原子的掺杂应保持在2:1左右的比例.     

Surface composition and structure of palladium ultra-thin films deposited on Ni(1 1 1)

Ultra-thin palladium films deposited on the Ni(1 1 1) surface were characterized by X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED) and X-ray photoelectron diffraction (XPD). For low coverage, LEED shows a (1 × 1) pattern similar to that of the substrate. For intermediate coverage, the LEED pattern displays extra spots around the main (1 × 1) spots, resembling a Moiré coincidence pattern, probably associated with the formation of Pd bi-dimensional islands oriented in different directions on the Ni(1 1 1) surface. The results obtained by XPS and XPD corroborate this finding. The LEED pattern displays this structure up to 500 °C. Annealing at 650 °C brings back the (1 × 1) pattern, which is associated with a Pd island coalescence and alloy formation by Pd diffusion in the first atomic layers of the Ni(1 1 1). In this paper we present a detailed study of this surface structure via a comparison between XPD experiment and theory.     

簇合物(I2InN3)n (n=1-4)的结构和稳定性的理论研究

为寻求单一源前驱体,采用密度泛函理论DFT-B3LYP方法系统研究新的第IIIA主族叠氮簇合物的结构与性质关系。结果表明,簇合物(I2InN3) n (n=2-4)的优化构型均为由不同子体系的叠氮基α−N和In原子相连形成的环状结构,叠氮基以直线型存在。研究了几何参数随聚合度的变化趋势,并对计算获得的IR谱进行归属。能量和聚合焓均揭示簇合物的稳定性次序为3A>3B和4B>4C>4A>4D。簇合物(I2InN3)n (n=1-4)的热力学函数随温度升高和聚合度n增大而増加。热力学分析表明聚合反应在温度高达500 K均可自发进行。     

Solvatochromism of Ternary Iron (II) Diimine Cyanide Complexes in 2-Ethyl-2-(hydroxymethyl) 1,3-Propanediol (Trimethylol Propane)

The solvatochromic behaviour of bis-(2,2′-bipyridyl)-biscyanoiron (II) and 2,2′- bipyridyltetracyanoiron (II) in 2-ethyl-2-(hydroxymethyl)-1,3-propanediol has been established. The significance and sensitivities of the solvatochromic shifts of these charge-transfer bands are outlined for the two iron complexes above.     

CuPc/ITO结构的表面和界面电子态的XPS研究

覆盖有Indium tin oxide(ITO)膜的透明导电玻璃广泛地用作有机发光器件 (OLEDs)的空穴注入电极 ,但是ITO膜的功函数通常与空穴传输材料的最高被占据分子轨道 (HOMO)不匹配。铜酞菁 (CuPc)作为缓冲层可以提高空穴从ITO向空穴传输材料的注入效率。对CuPc ITO样品的XPS表面分析表明 ,在CuPc分子中 ,铜原子显 2价 ,通过配位键和氮原子相互作用。CuPc分子中有两类碳原子 :8个C原子与 2个N原子成键 ;其余 2 4个C原子具有芳香烃性质。N原子也处在两种化学环境中 :有 4个N原子只与 2个C原子形成CNC键 ;另外 4个N原子不仅与 2个C原子成键 ,还通过配位键与Cu原子成键。用氩离子束对样品表面进行了溅射剥蚀 ,当溅射时间分别为 2 ,5 ,10min时进行XPS采谱分析 ,结果表明 ,随着氩离子束溅射时间增长 ,C 1s,N 1s峰变弱 ,Cu 2p ,O 1s,In 3d,Sn 3d峰增强 ,C 1s,N 1s,O 1s,In 3d和Sn 3d峰都向高束缚能或低束缚能方向移动 ,但它们的情况却不相同。     

Fabrication and characterization of superparamagnetic and thermoresponsive hydrogels based on oleic-acid-coated Fe3O4 nanoparticles, hexa(ethylene glycol) methyl ether methacrylate and 2-(acetoacetoxy)ethyl methacrylate

Stimuli-responsive hydrogel nanocomposites comprised of swollen polymer networks, in which magnetic nanoparticles are embedded, are a relatively new class of “smart” soft materials presenting a significant impact on various technological and biomedical applications. A novel approach for the fabrication of hydrogel nanocomposites exhibiting temperature- and magneto-responsive behavior involves the random copolymerization of hexa(ethylene glycol) methyl ether methacrylate (HEGMA, hydrophilic, thermoresponsive) and 2-(acetoacetoxy)ethyl methacrylate (AEMA, hydrophobic, metal-chelating) in the presence of preformed oleic-acid-coated magnetite nanoparticles (OA·Fe₃O₄). In total, two series of hydrogel nanocomposites have been prepared in two different solvent systems: ethyl acetate (series A) and tetrahydrofuran (series B). The degrees of swelling (DSs) of all conetworks were determined in organic and in aqueous media. The nanocrystalline phase adopted by the embedded magnetic nanoparticles was investigated by X-ray diffraction (XRD) spectroscopy. The obtained diffraction patterns indicated the presence of magnetite (Fe₃O₄). Deswelling kinetic studies that were carried out at ∼60 °C in water demonstrated the thermoresponsive properties of the hydrogel nanocomposites, attributed to the presence of the hexaethylene glycol side chains within the conetworks. Moreover, thermal gravimetric analysis (TGA) measurements showed that these materials exhibited superior thermal stability compared to the pristine hydrogels. Further to the characterization of compositional and thermal properties, the assessment of magnetic characteristics by vibrational sample magnetometry (VSM) disclosed superparamagnetic behavior. The tunable superparamagnetic behavior exhibited by these materials depending on the amount of magnetic nanoparticles incorporated within the networks combined with their thermoresponsive properties may allow for their future exploitation in the biomedical field.     

Evaluation of threading dislocation density of strained Ge epitaxial layer by high resolution x-ray diffraction

The analysis of threading dislocation density(TDD)in Ge-on-Si layer is critical for developing lasers,light emitting diodes(LEDs),photodetectors(PDs),modulators,waveguides,metal oxide semiconductor field effect transistors(MOS-FETs),and also the integration of Si-based monolithic photonics.The TDD of Ge epitaxial layer is analyzed by etching or transmission electron microscope(TEM).However,high-resolution x-ray diffraction(HR-XRD)rocking curve provides an optional method to analyze the TDD in Ge layer.The theory model of TDD measurement from rocking curves was first used in zinc-blende semiconductors.In this paper,this method is extended to the case of strained Ge-on-Si layers.The HR-XRD 2θ/ωscan is measured and Ge(004)single crystal rocking curve is utilized to calculate the TDD in strained Ge epitaxial layer.The rocking curve full width at half maximum(FWHM)broadening by incident beam divergence of the instrument,crystal size,and curvature of the crystal specimen is subtracted.The TDDs of samples A and B are calculated to be 1.41×10~8cm~(-2)and 6.47×10~8cm~(-2),respectively.In addition,we believe the TDDs calculated by this method to be the averaged dislocation density in the Ge epitaxial layer.     

1-(4-硝基苯)-3-(2-吡嗪)-三氮烯的合成及与锌(Ⅱ)的显色反应

报道了1-（4-硝基苯）-3-（2-吡嗪）-三氮烯（NPPT）的合成及与锌（Ⅱ）的显色反应。在非离子表面活性剂TritonX-100存在下,于pH8.8的KCl,H3BO3-NaOH缓冲介质中,NPPT与锌（Ⅱ）形成4∶1的黄棕色络合物,在465nm处有一最大吸收,表观摩尔吸光系数为3.15×104L·mol-1.cm-1,10mL溶液中,锌（Ⅱ）量在0—0.56μg范围内符合比尔定律。方法用于葡萄糖酸锌口服溶液中微量锌的测定,测定结果与AAS法相符。     

2-丙醇和1,1,1-三氟-2-丙醇在Ni(100)表面的裂解机理

本文研究了2-丙醇和1,1,1-三氟-2-丙醇在Ni(100)表面解离的可能微观反应机理,使用完全线性同步和二次同步变换(complete LST/QST)方法确定解离反应的过渡态.采用基于第一性原理的密度泛函理论与周期平板模型相结合的方法,优化了2-丙醇和1,1,1-三氟-2-丙醇裂解反应过程各物种在Ni(100)表面的top,hollow和bridge位的吸附模型,计算了能量,并对布局电荷进行了分析,得到了各物种的有利吸附位.结果表明:2-丙醇和1,1,1-三氟-2-丙醇在Ni(100)表面都存在β-H和γ-H两个平行竞争的解离过程,其中2-丙醇在Ni(100)表面β-H解离的速控步骤活化能为64.7 k J·mol-1猯,而γ-H解离速控步骤活化能为233.1 k J·mol-1猯,故β-H解离过程占优势,主要产物是CH3COCH3;相反,1,1,1-三氟-2-丙醇在Ni(100)表面β-H解离的速控步骤活化能为257.1 k J·mol-1猯,而γ-H解离速控步骤活化能为148.1 k J·mol-1猯,故γ-H解离过程占优势,主要产物是CF3CH=CH2.由此说明,电负性更大的氟原子取代2-丙醇中的氢原子之后,2-丙醇在Ni表面的解离机理发生了改变.理论预测结果与实验结论一致.     

2-丙醇和1,1,1-三氟-2-丙醇在Ni(100)表面的裂解机理

本文研究了2-丙醇和1,1,1-三氟-2-丙醇在Ni(100)表面解离的可能微观反应机理,使用完全线性同步和二次同步变换(complete LST/QST)方法确定解离反应的过渡态。采用基于第一性原理的密度泛函理论与周期平板模型相结合的方法,优化了2-丙醇和1,1,1-三氟-2-丙醇裂解反应过程各物种在Ni(100)表面的top,hollow和bridge位的吸附模型,计算了能量,并对布局电荷进行了分析,得到了各物种的有利吸附位。结果表明： 2-丙醇和1,1,1-三氟-2-丙醇在Ni(100)表面都存在β-H和γ-H两个平行竞争的解离过程,其中2-丙醇在Ni(100)表面β-H解离的速控步骤活化能为64.7 kJ∙mol-1,而γ-H解离速控步骤活化能为233.1kJ∙mol-1,故β-H解离过程占优势,主要产物是CH3COCH3;相反,1,1,1-三氟-2-丙醇在Ni(100)表面β-H解离的速控步骤活化能为257.1 kJ∙mol-1,而γ-H解离速控步骤活化能为148.1kJ∙mol-1,故γ-H解离过程占优势,主要产物是CF3CH=CH2。由此说明,电负性更大的氟原子取代2-丙醇中的氢原子之后,2-丙醇在Ni表面的解离机理发生了改变。理论预测结果与实验结论一致。     

Conformational analysis of 2,3-dihydro-3-O-(1,4-naphthoquinon-2-yl)-2-oxo-1,4-naphthoquinone derivatives by the density functional method and IR spectroscopy

We have used the PBE/3z, B3LYP/6-31G, B3LYP/6-31G(d), and B3LYP/6-311G(d) methods to study the conformational mobility of 2,3-dihydro-3-O-(1,4-naphthoquinon-2-yl)-2-oxo-1,4-naphthoquinones (1–4). We have shown that more than 99% of these compounds exist as the major tautomeric form, while differences in the structure of the Q_2H (2,3-dihydro-2-oxo-1,4-naphthoquinones) and Q_1,4 (1,4-naphthoquinon-2-yl) moieties lead to qualitative differences in the internal rotation potentials of the ethyl substituents V(θ_Et−1) and V(θ_Et−2), and consequently each of compounds 1−4 exists as six different rotameric forms. For diquinone 3, we have calculated the dependences of the frequencies (ν) and intensities (A) of the normal vibrations on the torsional angles θ_Et−1 and θ_Et−2, and also on the changes in the geometry of the ether bond. We have found that the values of ν and A for the bands in the carbonyl region of the IR spectrum change little on going from one rotameric form to another, and also for the in-plane bends of the ether bond, and change considerably for the out-of-plane bends of the ether bond. However, for T ≤ 300 K, there is no qualitative change in the overall contour, and it can be interpreted based on a simple additive model. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 573–581, September–October, 2006.     

Si(001)-(2*2*1):H表面O2吸附的密度泛函理论研究

建立了一种计算Si(001)-(2×2×1):H表面O2吸附的理论模型．在周期性边界条件下,采用基于密度泛函理论广义梯度近似的超软赝势法对Si(001)-(2×2×1):H表面O2吸附进行了第一性研究．通过占位能的计算,得到了Si(001)-(2×2×1):H表面O2的最佳吸附位置．计算结果表明吸附后的反应产物应为Si=O和H2O,从理论上支持了D．Kovalev等人提出反应机制．     

基于Ru(bpy)_3~(2+)印刷电极的电致化学发光传感器的研制

利用丝网印刷技术制备了基于Ru(bpy)23+(钌联吡啶)的印刷电极电致化学发光传感器,这种传感器具有制作简单、成本低、重现性好、对草酸盐的响应范围宽、检测限低等优点。详细研究了电极的制作方法以及发光试剂的固定化。在最优条件下,在pH 6.0的0.2 mol.L-1磷酸盐缓冲液中,利用所研制的ECL传感器测定C2O24-,线性响应范围为3.0×10-7~1.0×0-5mol.L-1,检测限为1.2×10-7mol.L-1(S/N=3)。根据同样的原理也可以用来测定其他的成分,如氨基酸,TprA(三丙胺),NAD(烟酰胺腺嘌呤二核苷酸)等物质。同时应该指出的是如果使用丝网印刷机器进行印刷的话,电极的重现性和稳定性还可以进一步提高。