十八硫醇/乙醇体系自组装膜对银的防变色作用

十八硫醇(ODT)是一种环境友好型金属处理剂。在乙醇体系中用十八硫醇在银表面制备自组装膜(SAMs)。采用加速变色、极化曲线、电化学阻抗、循环伏安等方法研究了乙醇溶液中十八硫醇自装膜对银表面的防变色作用。结果表明,在浓度为0.05mol/dm3,温度为50℃时,自组装最佳时间为1h,十八硫醇在银表面形成了一层致密的自组装膜,该膜具有良好的防变色效果。     

十八硫醇自组装膜对青铜-银电偶腐蚀的抑制作用

采用十八硫醇(ODT)的乙醇溶液在青铜和Ag表面制备了自组装膜(SAMs)。通过测量青铜-银的电偶电流和室内加速变色实验,研究了自组装前后的电偶腐蚀性能。采用XPS,Tafel极化曲线法和微分电容法初步研究了ODT SAMs的作用机理。结果表明:ODT分子通过S与基体形成硫醇盐,吸附在青铜和Ag表面形成自组装膜,该自组装膜在3.5%NaCl溶液和含S大气中,能够有效抑制青铜和Ag之间的电偶腐蚀,属于混和型缓蚀剂。     

水溶液中自组装膜对银的缓蚀作用及吸附机理分析

采用不同的分散剂将十八烷基硫醇(ODT)分散在水溶液中,并以其在银表面制备了自组装膜(SAMs)。用极化曲线、交流阻抗、循环伏安等电化学方法研究了ODTSAMs对银的缓蚀作用及吸附行为。结果表明:ODT分子能够在银表面形成稳定、致密的SAMs,有效抑制了银的阴极氧去极化过程和阳极硫化过程,改变了电极表面的双电层结构,对银有良好的缓蚀作用。ODT在银表面的吸附行为符合Langmuir吸附等温式,吸附机理是典型的化学吸附。     

十六硫醇自组装膜对Ag的防变色作用研究

针对Ag制品的变色问题,在Ag表面制备十六硫醇(HDT)自组装分子膜(SAMs),用H2S加速变色实验评价防变色效果,通过正交试验法得到最佳成膜工艺为:温度60℃,浓度0.1 mol/L,自组装时间为2 h。采用接触角测定和极化曲线、电化学阻抗、循环伏安曲线等电化学方法对膜的性能进行表征。结果表明:乙醇溶液中HDT在Ag表面形成了一层致密的自组装分子膜,具有良好的防变色效果。HDT SAMs对Ag腐蚀的阳极氧化和阴极还原均有抑制作用,膜的覆盖率为94.8%,缓蚀率达到95.9%。     

水溶液中自组装膜对青铜的缓蚀作用

采用不同的分散剂将十八烷基硫醇(ODT)分散在水溶液中,并以其在青铜表面制备了自组装膜(SAMs)。用极化曲线、交流阻抗、循环伏-安等电化学方法研究了ODT SAMs对青铜的缓蚀作用。结果表明:ODT分子能够在青铜表面形成稳定、致密的SAMs,有效抑制了青铜的阴极和阳极过程,改变了电极表面的双电层结构,对青铜有良好的缓蚀作用。     

Anticorrosion Action of Serf-assemble Monolayers on Bronze in Aqueous Solution

采用不同的分散剂将十八烷基硫醇(ODT)分散在水溶液中,并以其在青铜表面制备了自组装膜(SAMs).用极化曲线、交流阻抗、循环伏-安等电化学方法研究了ODT SAMs对青铜的缓蚀作用.结果表明:ODT分子能够在青铜表面形成稳定、致密的SAMs,有效抑制了青铜的阴极和阳极过程,改变了电极表面的双电层结构,对青铜有良好的缓蚀作用.     

十八硫醇自组装膜对青铜的缓蚀作用

在乙醇体系中采用十八硫醇(ODT)在青铜表面制备自组装膜(SAMs),采用循环伏安法、极化曲线和交流阻抗谱等电化学方法研究该膜在0.5 mol/LNaCl溶液中对青铜电极的缓蚀性能。结果表明:ODT在青铜表面形成了SAMs,能够有效抑制青铜的腐蚀。随着成膜温度和ODT浓度的增高,ODT自组装膜的缓蚀效率和覆盖度提高。当ODT浓度为0.1 mol/L、成膜温度为60℃时,缓蚀效率为98.1%,覆盖度为98.7%;十八硫醇在青铜表面的吸附行为符合Langmuir吸附等温式,吸附机理是典型的化学吸附。     

十二烷基硫醇在Fe表面自组装成膜及对其的腐蚀保护

应用自组装技术在Fe电极表面制备正、叔十二烷基硫醇自组装膜,用反射傅立叶红外光谱（FT-IR）、电化学阻抗谱（EIS）和Tafel极化曲线对正、叔十二烷基硫醇自组装膜进行表征,结果表明,正、叔十二烷基硫醇都能在Fe表面形成自组装膜;设计了自组装膜的等效电路,并对EIS数据进行拟合;EIS拟合结果和Tafel极化曲线均表明,正、叔十二烷基硫醇自组装膜对Fe电极在 0.5 mol/L NaCl溶液中均具有较好的缓蚀作用,并且前者的缓蚀作用强于后者。     

烷基硫醇自组装膜对铝合金的缓蚀性能研究

采用浸泡法,在含水量不同的十四烷基硫醇/乙醇-水溶液中,使2024铝合金表面自组装烷基硫醇膜,通过动电位扫描、电化学交流阻抗、原子力显微镜以及光电子能谱研究了硫醇自组装膜在铝合金表面的吸附行为及缓蚀性能。结果表明,十四烷基硫醇自组装膜对铝合金在Harrison溶液中的腐蚀具有一定缓蚀作用,且缓蚀效果随着自组装溶液中含水量的增加而增强。     

银币表面自组装膜抗变色性能及成膜机理

利用化学方法在银币表面制备了十八烷基硫醇组装膜(C18SHSAMs),并通过电化学技术研究了其在0.5mol/LNaCl+0.01mol/LNa2S溶液中的抗变色性能。结果表明:银表面形成SAMs后腐蚀电位正移30mV;阴极氧去极化和阳极银的硫化过程均受到抑制,对阴极极化过程的阻滞作用较阳极极化过程明显;银表面成膜后,容抗弧、电荷传递系数Rt增大,双电层电容Cd降低。有效提高银币的抗变色性能。银表面C18SHSAMs的形成过程符合两阶段模型。膜初始吸附阶段(I)为2级Langmuir吸附,重整结晶阶段(Ⅱ)为1级Langmuir吸附,动力学公式分别为,Ⅰ阶段:ctctt11.7061.706,Ⅱ阶段:0.5471ectt。速率常数与温度的关系为ln(k)=–5826/T+26.5,自组装过程表观活化能E=48.4kJ/mol,化学吸附为控制步骤。     

2-Mercaptobenzothiazole monolayers on zinc and silver surfaces for anticorrosion

Anticorrosive behaviors of 2-mercaptobenzothiazole (MBT) self-assembled monolayers (SAMs) on silver and zinc electrodes were comparatively studied by means of electrochemical impedance spectroscopy (EIS). The promising inhibition effect of the MBT for silver and zinc from corrosion had been confirmed. The adsorption geometries of MBT monolayers on zinc and silver electrodes were observed by surface enhanced Raman scattering (SERS) technique. The SERS spectra implied that monolayers of MBT could be self-assembled on Ag surface through S¹⁰ and N³ atoms and the molecular plane should be tilted with respect to the surface. On Zn surface, MBT molecules formed monolayers via both S atoms and the other moieties of the molecule away from the surface. From the in situ electrochemical SERS results it can be found that MBT monolayers on both Ag and Zn surfaces experienced the changes of adsorption fashions as the potential shifting to more negative direction.     

Stabilization of a surface plasmon resonance (SPR) optical fibre sensor with an ultra-thin organic film: application to the detection of chloro-fluoro-carbon (CFC)

Surface plasmon resonance (SPR) is a powerful technique for direct sensitive (bio) chemical detection. This phenomenon can be used to measure the refractive index of either bulk chemical samples or chemically sensing thin layers. In this work, a SPR fibre optic sensor has been developed. A 50 nm thick silver film is deposited by thermal evaporation onto the silica core of the optical fibre. To protect silver from oxidation, the evaporated silver film was covered with self-assembled monolayers (SAMs) of long-chain alkanethiols (1-octadecanethiol). To characterize these SAMs, silver films evaporated onto macroscopic glass surfaces as test samples and several techniques such as contact angle measurements (sessile drop method), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were used. In the subsequent step, a chemically sensing thin layer (polyfluorosiloxane) was deposited onto the thiol surface. In such a configuration the SPR fibre optic sensor was able to detect a few percent of chloro-fluoro-carbon (CFC) vapours.     

谷氨酸自组装膜对铜的缓蚀机理研究

用电化学测量法研究不同组装时间、不同组装浓度和不同pH情况下谷氨酸自组装单分子膜（SAMs）对铜在0.5 mol/L HCl中的缓蚀作用,考察碘离子和谷氨酸单分子膜的协同作用,并通过量子化学计算探讨谷氨酸在铜表面的吸附机理。结果表明,谷氨酸自组装膜的缓蚀效率随组装时间和组装浓度的增加递增,最佳组装条件是在10 mmol/L组装溶液中组装12 h;在 pH=10下形成的自组装单分子膜的缓蚀作用要优于其他pH下形成的自组装膜,碘离子的加入可进一步提高谷氨酸自组装膜对铜的保护效果。     

水溶液中银表面自组装膜工艺

采用银在水溶液表面形成C18SH自组装膜(SAMs)的工艺,在银表面得到致密、平整,表现出明显疏水性的SAMs。EMPA和XPS测试表明,表面活性剂分别作为C18SH的分散剂,自组装过程中起到传输作用,本身不参与成膜,但影响SAMs的厚度和倾斜角。银试样表面的Ag2O在成膜过程中被硫醇中的H-S键还原为Ag,同时有Ag-S-C18H37键的形态形成。     

自组装硅烷膜对 6061 铝合金表面耐蚀性影响的研究

采用自组装方法,在6061铝合金表面制备十二氟庚基丙基三甲氧基硅烷自组装膜层,对制备工艺进行了优化,并对自组装膜层进行了表面形貌分析,通过极化曲线和电化学阻抗谱研究了自组装膜层的耐蚀性能。结果表明:与铝合金基体相比,自组装膜的腐蚀电流密度减小了3个数量级,电化学阻抗值增大了近1倍,达到了提高铝合金表面耐蚀性能的目的。     

Tarnish protection of silver by octadecanethiol self-assembled monolayers prepared in aqueous micellar solution

Silver will tarnish when it is exposed to the sulfur polluted atmosphere. Self-assembled monolayers are an efficient, invisible and protective film against tarnishing. SAMs prepared by the adsorption of octadecanethiol onto silver in aqueous micellar solution are explored. The silver was first degreased by acetone in an ultra-sonicate bath, followed by activation in 10% sulphuric acid solution, then, immersed in aqueous micellar solution with 0.15 mol/L octadecanethiol and 40 g/L Cetane trimethyl ammonium bromide (CTAB), Triton X-100 (TX-100), Polyoxyethylene lauryl ether (PLE) or Pluronic PE6400 during 5 min at 60 °C. The film was characterized by contact angles, FT-IR, XPS and AFM. The film was totally composed of octadecanethiol and was influenced by the surfactant in the thickness and tilt angle. The anti-tarnishing ability of the film on the silver was evaluated by electrochemical measurements in 0.5 mol/L NaCl solution containing 10 mmol/L Na₂S. The protection efficiency reached 91.9% The electro-oxidation reaction process was reduced substantially in 0.5 mol/L NaOH solution. EIS data proved that the inhibition of the monolayers was marked and the coverage of the film was more than 94.5%. The color, gloss and reflectance of silver with SAMs were almost similar to the bare silver. It was found that after 48 h accelerated tarnishing test, the protection of the thiol film remained efficient. The film controlled markedly the transfer of ion to the surface and the sulfuration rate of silver was reduced substantially.     

Inhibition Effect of 2,4,6-Trimercapto-1,3,5-triazine Self-Assembled Monolayers on Copper Corrosion in NaCl Solution

2,4,6-Trimercapto-1,3,5-triazine (TMTA) was self-assembled on copper surface by a simple method and the resulting self-assembled monolayers (SAMs) were characterized by FTIR and contact angle. It was found that TMTA dissolved in aqueous solution could be adsorbed rapidly on the copper surface and yielded a hydrophilic surface. The inhibition effect of TMTA SAMs on copper corrosion in 0.5 M NaCl solution was investigated through potentiodynamic polarization curves and electrochemical impedance spectroscopy. Results indicated that TMTA SAMs acted as a mixed type corrosion inhibitor with predominant control of cathodic reaction. The inhibition efficiency increased with increasing assembly time but decreased to some extent with increasing concentration of chloride ions. Immersion test revealed the SAMs could keep good stability and durability in 0.5 M NaCl solution. From the experimental and theoretical study, the mechanisms of TMTA SAMs formation and corrosion protection for copper were discussed.