铜电极表面硅烷膜的自组装及其性能研究

应用自组装技术在铜电极表面上制备3巯基丙基三甲氧基硅烷自组装膜.红外光谱研究该自组装膜结构,电化学方法考察3-巯基丙基三甲氧基硅烷膜在5%NaCl溶液中对铜电极的缓蚀性能.结果表明,于不同浓度的3-巯基丙基三甲氧基硅烷乙醇溶液中自组装的硅烷膜表现出较好的抗腐蚀性.     

一种简单组装纳米沸石粒子层的方法及其二次法成膜研究

使用一种简单、新颖的纳米沸石晶体自组装方法, 以γ-氨丙基三甲氧基硅烷(AP-TMS)为偶联剂, 成功地实现了纳米A型沸石粒子在多孔不锈钢、陶瓷以及单晶硅表面的沉积组装, 获得了覆盖度高的续、均匀的沸石粒子层. 组装过程在合成釜内分为载体功能化和晶种化两步. 以该沸石粒子层为晶种二次法成膜, 形成了交织生长的连续、均匀的沸石膜, 并用含少量水的苯甲醛混合液评价了微型膜的渗透蒸发性能, 水-苯甲醛分离系数超过10 000以上. 考察了使用γ-氨丙基三甲氧基硅烷(AP-TMS)、γ-氯丙基三甲氧基硅烷(CP-TMS)和γ-巯丙基三甲氧基硅烷(SP-TMS)三种不同偶联剂时, 纳米A型沸石晶体在多孔不锈钢、陶瓷以及单晶硅表面的自组装效果. 研究发现, 使用CP-TMS作为偶联剂时, 只在不锈钢载体上形成较为连续的粒子层, 而使用SP-TMS作为偶联剂时, 在三种载体上纳米A型沸石粒子均不能沉积形成粒子层. 对偶联剂的作用和粒子组装机制进行了讨论和预测.     

原子层沉积法制备巯丙基硅胶及其对溶液中钯(Ⅱ)离子的吸附行为

采用原子层沉积技术, 在3~5 kPa真空和125~150 ℃ 的反应条件下, 使γ-巯丙基三甲氧基硅烷(MPTMS)、γ-巯丙基三乙氧基硅烷(MPTES)和γ-巯丙基二甲氧基甲基硅烷(MPDMMS)3种巯丙基硅烷试剂气化, 并在三乙胺的催化作用下, 分别将其键合于多孔硅胶表面, 制得贵金属钯(Ⅱ)的高效吸附剂. 分别采用FTIR、¹³C和²⁹Si固体核磁、元素分析、热重分析和氮气吸附-脱附等技术研究了巯基硅胶的键合模式和功能基团键合量. 用分光光度法研究了在pH=3.0条件下水溶液中Pd(Ⅱ)离子在巯基硅胶上的吸附行为. 结果表明, 在MPTMS, MPTES和MPDMMS所修饰的硅胶中, 硅烷试剂的功能基团均以双齿键合结构为主, 表面键合量分别达到2.76, 2.53和2.70 μmol/m². 对Pd(Ⅱ)离子的吸附遵从Langmuir等温吸附方程, 饱和吸附量分别达到5.45, 4.21和4.81 μmol/m², Pd/S的摩尔比分别为1.44, 1.35和1.39. 原子层沉积法制备的巯丙基硅胶基质钯吸附剂的巯基键合密度和对钯(Ⅱ)离子的吸附容量均比传统的有机溶剂介质法高.     

电镀锌钢硅烷-有机膦酸复合钝化膜的制备及性能表征

利用N-(β-氨乙基)-γ-氨丙基三甲氧基硅烷(AAPTMS)、γ-(2,3-环氧丙氧基)丙基三甲氧基硅烷(GPTMS)和1-羟基亚乙基-1,1-二膦酸(HEDP),在电镀锌钢基体上制备了一种新型硅烷-有机膦酸复合钝化膜.X射线光电子能谱、傅立叶变换红外光谱以及中性盐雾试验、动电位极化曲线和电化学阻抗谱测试表明:该复合钝化膜主体结构由Si—O—Si、Si—O—P等组成;120 h中性盐雾试验后白锈面积小于5%,达到铬酸盐彩色钝化膜水平;且其腐蚀反应呈现更为明显的阳极扩散控制特征,属于物理阻挡机制.     

氟硅烷自组装单分子膜的制备及其摩擦学性能

利用分子自组装技术制备了全氟辛酰胺丙基硅烷单分子膜,用X射线光电子能谱(XPS)对组装膜的表面元素进行了表征;接触角测试表明,该组装膜具有很好的疏水-疏油性,其对水的接触角高达105°,对正十六烷的接触角为50°.摩擦磨损实验结果表明,全氟辛酰胺丙基硅烷自组装单分子膜可以大大降低基片的摩擦系数,使载玻片的摩擦系数从0.85左右降低到0.14左右,而且低负荷下具有很好的耐磨性.     

功能性硅烷在纳米氧化硅表面的自组装

在分散体系中,两种功能性硅烷,甲基丙烯酰氧丙基三甲基硅烷(MPTES)和氨丙基三甲基硅烷(APTES)在纳米氧化硅表面形成自组装单分子层,用XPS 和FTIR对所得自组装单分子层进行了表征.元素分析结果表明,所得功能性纳米氧化硅中的功能基含量分别为1.03 mmol/g甲基丙烯酰氧基/丙烯酰氧丙基纳米氧化硅(MPSN)和3.34 mmol/g氨基/氨丙基纳米氧化硅(APSN).LSS 分析结果表明,未修饰纳米氧化硅、 MPSN和APSN在甲苯分散体系中的平均流体力学直径大约分别为240、 45和560 nm.     

金在氨基硅烷修饰SBA-15上的巴豆醛选择加氢性能

采用三种氨基硅烷试剂(APTS: 3-氨丙基三甲氧基硅烷, TPED: N-(2-氨乙基)-3-氨丙基三甲氧基硅烷, TPDT: 3-[2-(2-氨基乙基氨基)乙基氨基]丙基-三甲氧基硅烷)对介孔SBA-15分子筛进行后嫁接表面功能化(分别记为APTS-SBA-15, TPED-SBA-15和TPDT-SBA-15), 然后利用氨基与氯金酸之间的静电作用及化学还原法, 将金纳米粒子引入分子筛的介孔孔道. 采用N₂物理吸附、X射线衍射(XRD)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)等手段对催化剂的结构和电子性质进行了系统表征; 以巴豆醛液相加氢制巴豆醇反应比较了氨基硅烷的种类对催化性能的影响. 结果表明, 氨基硅烷的给电子能力是决定金催化剂上C＝O键加氢选择性的主要因素, 氨基硅烷的给电子能力越强, 金活性位上的电子密度越高, 则巴豆醇的选择性和收率就越高.     

氟硅烷自组装单分子膜的制备及其摩擦学性能

利用分子自组装技术制备了全氟辛酰胺丙基硅烷单分子膜,用X射线光电子能谱(XPS)对组装膜的表面元素进行了表征;接触角测试表明,该组装膜具有很好的疏水疏油性,其对水的接触角高达105°,对正十六烷的接触角为50°.摩擦磨损实验结果表明,全氟辛酰胺丙基硅烷自组装单分子膜可以大大降低基片的摩擦系数,使载玻片的摩擦系数从0.85左右降低到0.14左右,而且低负荷下具有很好的耐磨性.     

金纳米粒子在平整硅基表面上的组装

采用水相硅烷化方法,将３－氨基丙基－三甲氧基硅烷（ＡＰＳ）组装在湿化学法处理的单晶硅表面上。接触角、原子力显微镜（ＡＦＭ）、Ｘ射线光电子能谱（ＸＰＳ）表征结果显示得到了平整均匀的具有氨基表面的自组装膜。ＳＥＭ观察表明,１６ｎｍ的金纳米粒子可以在上述氨基表面上形成均匀的亚单层排布,得到了具有Ａｕ纳米粒子／ＡＰＳ／Ｓｉ形成的纳米复合结构,进一步的处理可以使金纳米粒子在表面上的排列由随机趋于有序化。     

Janus纳米材料的制备及结构调控

用3-(甲基丙烯酰氧)丙基三甲氧基硅烷(MPS)、 氨丙基三乙氧硅烷(APTES)和正硅酸乙酯(TEOS)溶胀聚苯乙烯中空微球的壳层, 在壳层表面通过溶胶-凝胶过程, 使亲油和亲水基团通过自组装作用分别朝向聚苯乙烯基体和水相, 形成Janus结构. 用良溶剂N,N-二甲基甲酰胺(DMF)溶解除去聚苯乙烯, 得到二氧化硅基复合Janus纳米材料. 改变反应体系pH值和单体用量等可以调控Janus纳米材料微结构, 得到Janus中空球和纳米片.     

正、叔十二烷基硫醇在铜表面上自组装膜测试

研究了正、叔十二烷基硫醇在铜表面上的自组装及混合自组装成膜情况,并利用交流阻抗和极化曲线电化学方法测试了正、叔十二烷基硫醇在铜表面上自组装膜及混合自组装膜对铜的耐腐蚀性,考察了正十二烷基硫醇自组装膜质量与正十二烷基硫醇溶液的浓度及组装时间的关系。研究结果显示,混合自组装膜的质量及其对铜的耐腐蚀性比仅组装正或叔十二烷基硫醇均有很大的提高。     

Surface modification of microporous polypropylene membranes by the grafting of poly(γ-stearyl-l-glutamate)

A polypeptide, poly(γ-stearyl-l-glutamate) (PSLG), was grafted on the surface of hydrophobic polypropylene hollow fiber membranes through the ring opening polymerization of N-carboxyanhydride (NCA) of γ-stearyl-l-glutamate initiated by amino groups which was generated by ammonia plasma. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), together with water contact angle and bovium serum albumin adsorption measurements were used to characterize the modified membrane surface. The XPS and FT-IR spectra demonstrated that polypeptide was actually grafted on the membrane surface despite of the low degree of graft polymerization due to the hydroxyl groups on the membrane surface. To subject the ammonia plasma-treated membrane with γ-(aminopropyl)triethanoxysilane (γ-APS) which can react with hydroxyl groups and leave amino groups, the degree of graft polymerization could be improved. The bovium serum albumin adsorption measurement was conducted to further examine the surface properties of modified and original membranes. Potential applications of the PSLG grafted membranes are expected for enantiomer separation and/or enzyme immobilization.     

A pathway of free radical generation via copper corrosion and its application to oxygen and ozone activation for the oxidative destruction of organic pollutants

This study investigated the commercially available zero-valent copper powder and copper foil to activate molecular oxygen (O₂) and ozone for the degradation of organic pollutants. Under aerobic atmospheric conditions, copper powder effectively removed 50 mg/L of acetaminophen (ACT) within 2 h, though the degradation rate using the foil was less than 20% of the powder. However, copper foil activated ozone to effectively degrade ACT. The total organic carbon (TOC) removal reached a high of 58.3% at a catalyst concentration of 40 g/L, but only 26.8% with ozone alone. The initial solution pH and dosage of copper foil were key operational parameters affecting the ozone activation process. H₂O₂ and Cu(I) were important intermediates in the process as hydroxyl radicals (^·OH) were identified via EPR (electron paramagnetic resonance) experiments and free radical scavengers. The generation of ^·OH was attributed to a Fenton-like reaction between Cu(I) and H₂O₂; this free-radical generation mechanism differs from typical transition metal oxide catalysts. This study outlines a promising approach to significantly increase the generation of ^·OH and effectively remove refractory organic compounds. Furthermore, these copper products are applied in structural components of practical water treatment. Thus, the study of corrosion resistance to oxygen and ozone in aqueous solution have both a practical and theoretical significance. It was determined that copper products were resistant to oxygen corrosion in aqueous solution, but not resistant to ozone corrosion.     

A Metallic Surface Corrosion Study in Aqueous NaCl Solutions Using Atomic Force Microscopy (AFM)

We report an upper-division undergraduate solid-state materials chemistry experiment involving the pit and crevice corrosion of a copper surface caused by an aqueous NaCl solution simulating a seawater environment. Surface corrosion of the copper can be shown quite dramatically using atomic force microscopy (AFM) within only hours of exposure to the saline solution. The copper surfaces can also be treated with an alkanethiol solution to form a self-assembled monolayer (SAM) on the surface. When exposed to the salt-water solution, the SAM layer is shown by AFM to protect the surface from corrosion. We have also shown that several different AFM analysis methods are needed to adequately quantify the surface features including roughness and power spectral density. This experiment enables students to not only see how AFM can be used to observe changes in surface morphology, but also learn to develop an understanding of the analysis techniques used to quantify AFM data.     

Characteristics and retention properties of a mesoporous γ-Al2O3 membrane for nanofiltration

A mesoporous γ-Al₂O₃ membrane was produced by the sol gel dipping technique, followed by a thermal treatment (calcination and sintering). Different sintering temperatures were applied, which led to membranes with an average pore diameter ranging from 8.7 to 3.4 nm, the latter one corresponding to a MWCO of 900 Da.Salt retention was very much dependent on the pH of the solution as such membranes have an amphoteric character. Minimal salt retention was found at the isoelectric point (pH 7.5). Experiments were carried out with NaCl, MgCl₂ and LaCl₃ at different concentrations and in both single salt solutions and mixtures. The results are interpreted in terms of Donnan exclusion and in terms of the formation of an electrical double layer in the pores.Dynamic corrosion tests showed that some corrosion occurs at a pH of 2 or lower.     

铜表面二硫代氨基甲酸改性葡萄糖自组装膜的缓蚀作用

合成了一种环境友好型的缓蚀剂--二硫代氨基甲酸改性葡萄糖（DTCG）。 采用该缓蚀剂在铜表面制备了自组装膜,并运用电化学阻抗谱、极化曲线方法研究了该膜在3%NaCl溶液中对铜的缓蚀性能。 研究结果表明,DTCG自组装膜对铜有良好的缓蚀效果,在自组装时间为4 h、自组装浓度为120 mg/L的缓蚀效率接近于97%。 量子化学计算结果也证明了DTCG具有优异的缓蚀性能。     

Self-assembled polyelectrolyte multilayered films on Nafion with lowered methanol cross-over for DMFC applications

The paper is concerned with the deposition of self-assembled polyelectrolyte multilayer on Nafion membrane by layer-by-layer (LbL) technique with lowered methanol cross-over for direct methanol fuel cell (DMFC) applications. The formation of self-assembled multilayered film on Nafion was characterized by UV–vis spectroscopy and it was found that the polyelectrolyte layers growth on the Nafion surface regularly. Furthermore, the proton conductivity and methanol cross-over measurements were carried out for characterization of the LbL self-assembled composite membranes. The results showed that the concentration and pH of the polyelectrolytes significantly affect the proton conductivity and methanol barrier properties of the composite membranes. 10⁻¹ monomol polyelectrolyte concentration and pH 1.8 was found to be optimum deposition conditions considering proton conductivity and methanol permeation properties of the LbL self-assembled composite membranes. The methanol permeability of the 10 bi-layers of PAH1.8/PSS1.8 deposited LbL self-assembly composite membrane was significantly suppressed and found to be 4.41 × 10⁻⁷ cm²/s while the proton conductivity value is in acceptable range for fuel cell applications.     

吡咯烷二硫代氨基甲酸铵自组装膜对铜的缓蚀作用

吡咯烷二硫代氨基甲酸铵(APDTC)是一种环境友好型金属缓蚀剂, 以其在铜表面制备了自组装单分子膜(SAMs), 用电化学方法研究在0.5 mol·L-1 HCl介质中APDTC SAMs对铜的缓蚀作用及其吸附行为. 结果表明, APDTC分子易在铜表面形成稳定的APDTC SAMs, 改变了电极表面的双电层结构, SAMs同时抑制了铜的阳极氧化过程和阴极还原过程, 铜电极的电荷转移电阻明显提高, 双电层电容明显降低. 电化学阻抗和极化曲线测试结果显示, 在0.5 mol·L-1 HCl介质中, 铜表面APDTC SAMs表现出良好的缓蚀效果. 研究结果还表明, APDTC的吸附行为符合Langmuir吸附等温式, 吸附机理是介于化学吸附和物理吸附之间的一种吸附.     

Inhibition of copper corrosion by self-assembled monolayers of triazole derivative in chloride-containing solution

The self-assembled monolayers (SAMs) derived from 3-undecane-4-amino-5-mercapto-1,2,4-triazole (UAMT) on copper surface have been characterized by contact angle test, X-ray photoelectron spectroscopy, and electrochemical techniques. It is found that the UAMT molecules can spontaneously adsorb to copper surface to form compact and oriented monolayers, which can prevent the corrosion of copper in chloride-containing solution effectively. The electrochemical measurements prove that the adsorption of UAMT molecules on copper surface typically processes with a two-step adsorption consisting of a fast initial adsorption and a slowly following reorganization in 10^?4-M UAMT solution, and the adsorption of UAMT obeys the Langmuir model in the initial adsorption process. Furthermore, the effects of the immersion time, ultrasonic irradiation, and UAMT concentration on the anticorrosion property of SAMs are studied, and the adsorption isotherm of UAMT on copper is followed.