4-氨基苯甲酸席夫碱自组装缓蚀膜对20#钢在饱和CO2油田水中的缓蚀性能

利用邻氧乙酸苯甲醛缩4-氨基苯甲酸钾盐席夫碱(K₂L1)缓蚀剂在20#碳钢表面制备了自组装单分子膜(SAMs),通过电化学方法研究了缓蚀剂的合成条件、自组装时间等因素对成膜的影响,结果表明,合成中KOH与邻氧乙酸苯甲醛按2:1摩尔比进行反应得到的K₂L1缓蚀剂在碳钢表面自组装3 h后,可以形成稳定、致密的缓蚀膜。缓蚀性能的研究表明,碳钢表面K₂L1-SAMS抑制了碳钢的阴极还原过程,改变了电极表面双电层结构,具有良好的缓蚀效果(最高缓蚀效率可达95%以上),交流阻抗和极化曲线得到的结论是一致的。同时研究表明K₂L1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。量子化学计算结果表明,K₂L1分子具有多个吸附活性中心,这些活性原子的前线轨道能与碳钢表面铁原子的前线轨道相互作用,因而使得K₂L1分子在碳钢表面形成吸附膜,阻止了碳钢在饱和CO₂油田水介质中的溶解。X射线光电子能谱(XPS)分析表明,K₂L1通过配位键在碳钢表面形成了稳定的缓蚀膜。     

自组装席夫碱膜对铜的缓蚀行为

通过分子自组装技术在铜表面制备2-氨基-5-巯基-1,3,4-噻二唑缩对羟基苯甲醛（简称A）和2-氨基苯并咪唑缩对羟基苯甲醛（简称B）缓蚀膜。采用电化学测试方法研究了两种席夫碱自组装膜在质量分数为3%的NaCl溶液中对铜的缓蚀作用。结果表明,自组装分子膜能有效抑制铜片的腐蚀,对于席夫碱A,当溶液浓度为15 mmol·L^-1,组装时间为6 h时缓蚀效果最佳;对于席夫碱B,当溶液浓度为20 mmol·L^-1,组装时间为12 h时缓蚀效果最佳,A、B的缓蚀效率分别达到98.9%和96.73%。表面分析技术表明,席夫碱化合物在铜表面形成一层保护膜,有效阻挡了腐蚀粒子向金属基底的转移,从而抑制了腐蚀的发生。量化计算和分子动力学模拟分析了A、B两种缓蚀剂分子构型与缓蚀性能的关系以及在铜表面的吸附形态,结果表明,两种缓蚀剂具有很好的缓蚀性能,且缓蚀效果A>B,与实验结果一致。     

自组装席夫碱膜对铜的缓蚀行为

通过分子自组装技术在铜表面制备2-氨基-5-巯基-1,3,4-噻二唑缩对羟基苯甲醛(简称A)和2-氨基苯并咪唑缩对羟基苯甲醛(简称B)缓蚀膜。采用电化学测试方法研究了两种席夫碱自组装膜在质量分数为3%的NaCl溶液中对铜的缓蚀作用。结果表明,自组装分子膜能有效抑制铜片的腐蚀,对于席夫碱A,当溶液浓度为15 mmol?L-1,组装时间为6 h时缓蚀效果最佳;对于席夫碱B,当溶液浓度为20 mmol?L-1,组装时间为12 h时缓蚀效果最佳,A、B的缓蚀效率分别达到98.9%和96.73%。表面分析技术表明,席夫碱化合物在铜表面形成一层保护膜,有效阻挡了腐蚀粒子向金属基底的转移,从而抑制了腐蚀的发生。量化计算和分子动力学模拟分析了A、B两种缓蚀剂分子构型与缓蚀性能的关系以及在铜表面的吸附形态,结果表明,两种缓蚀剂具有很好的缓蚀性能,且缓蚀效果AB,与实验结果一致。     

植物提取物自组装膜在盐酸中对Q235钢的缓蚀作用

以铁线蕨植物提取物(ACE)为成膜物质,在Q235钢表面自组装得到缓蚀膜。通过极化曲线和电化学阻抗谱测试研究了该自组装膜对Q235钢在1 mol/L HCl溶液中的缓蚀性能。结果表明,该自组装膜对Q235钢的阴、阳极腐蚀反应均有抑制作用,可明显减缓Q235钢在盐酸溶液中的腐蚀,且缓蚀作用随ACE质量浓度的增大而增强。ACE分子在Q235钢表面的吸附遵从Langmuir和Frumkin吸附模型,为单分子层吸附,吸附分子之间存在横向吸引力。     

规整有机分子自聚集体对铜的高效缓蚀的研究

通过多步法合成了离子型含双苯并三氮唑环的目标分子，4，4'-{苯-1，3-二基二[(1E)-3-羰基丙-1-烯-1，3-二基]}二[2-(2H-苯并三唑-2-基)苯醇酸]二钾。在室温条件下，目标分子在3.5%（质量）NaCl/DMSO（二甲基亚枫）混合溶液 （体积比：40/60） 中能够发生分子自组装产生纳-微米级的自聚集体。通过傅里叶变换红外光谱 （FT-IR）、拉曼光谱和X射线光电子能谱 （XPS） 的表征，证实了所形成的目标分子自聚集体能够对铜表面产生强烈的化学吸附作用，在铜表面形成自组装膜。利用电化学方法测定了目标分子自聚集体吸附在铜表面形成自组装膜后，在3.5%（质量）NaCl溶液中的缓蚀性能。结果表明目标分子自聚集体在NaCl溶液中能高效地抑制铜腐蚀。     

聚乙二醇改性3,5-二溴水杨醛缩对氨基苯甲酸席夫碱对铝缓蚀性能研究

合成一种聚乙二醇酯改性席夫碱缓蚀剂,考察其对铝的缓蚀性能。以3,5-二溴水杨醛、对氨基苯甲酸为原料,经溶液法,合成了3,5-二溴水杨醛缩对氨基苯甲酸席夫碱,利用红外光谱、紫外光谱对其结构进行表征与确认。利用硼酸酯化法合成聚乙二醇(1000)单月桂酸酯,测定其酸值、皂化值分别为34 mg/g KOH,112 mg/g KOH。以N,N-二甲基甲酰胺为溶剂,对甲苯磺酸为催化剂,在常压下,反应温度为130℃,合成聚乙二醇改性3,5-二溴水杨醛缩对氨基苯甲酸席夫碱缓蚀剂。以纯铝片为研究对象,运用分子自组装技术,在铝表面自组装成膜,利用电化学技术、失重法和扫描电子显微分析法探讨聚乙二醇酯改性席夫碱自组装膜在0.5 mol/L盐酸溶液中对铝的缓蚀作用。结果表明,当缓蚀剂浓度为100 mg/L时,自组装时间为30 min,对铝的缓蚀效果最佳。     

噁二唑缓蚀膜的制备及抗腐蚀性能研究

以二芳基酰肼为原料合成2,5-二苯基-1,3,4-噁二唑(PPD),在碳钢表面制备噁二唑自组装分子膜。采用表面分析技术、电化学测试等方法对PPD分子膜的制备条件及在3.5% NaCl溶液中的缓蚀性能进行了分析,通过量化计算对缓蚀机理进行了进一步的探讨。结果表明,PPD自组装膜的最佳组装条件为4 mmol•L-1组装液中组装12h,缓蚀效率达91.95%,XPS测试结果表明PPD分子在钢表面形成自组装膜,量化计算得到了缓蚀剂分子的活性位点。     

金属表面烷基硫醇类自组装膜的研究进展

自组装膜(SAMs)是活性分子通过化学键自发吸附在基底上的有序分子膜,由于其排列紧密、结构稳定,因此对基底金属具有良好的防腐蚀作用.本文综述了近年来烷基硫醇类自组装膜在金、铜、铁和其他金属表面缓蚀中的发展和现状.     

曼尼希碱和钨酸钠溶液与铜的分子动力学模拟

利用分子动力学模拟研究了曼尼希碱与钨酸钠溶液中各粒子在铜表面的吸附作用,并分析了吸附能力随温度的变化。计算结果表明:铜的不同切平面对缓蚀剂分子的吸附能不同;曼尼希碱和钨酸钠与铜的交互作用能远大于腐蚀液中其他粒子与铜的交互作用能,说明曼尼希碱和钨酸钠可以较容易的吸附在铜表面形成缓蚀层,有效阻止铜的腐蚀;该缓蚀剂在较大的温度跨度下有较好的缓蚀效率,尤其在60℃左右时钨酸钠与曼尼希碱在铜表面的吸附能分别能达到-25.38kcal/mol与-76.07kcal/mol,缓蚀效率最高。     

噁二唑缓蚀膜的制备及抗腐蚀性能

以二芳基酰肼为原料,合成2,5-二苯基-1,3,4-噁二唑(PPD),在碳钢表面制备噁二唑自组装分子膜。采用电化学测试、表面分析等方法对PPD分子膜的制备条件及其在质量分数3.5%NaCl溶液中的缓蚀性能进行了分析,通过量化计算对缓蚀机理进行了进一步探讨。结果表明,PPD自组装膜的最佳组装条件是:在4 mmol/L PPD组装液中组装12 h,缓蚀效率达91.95%。XPS测试结果表明,PPD分子在钢表面形成了自组装膜。量化计算得到了缓蚀剂分子的活性位点,PPD的N原子同时具有较大的Fukui(-)(0.076)和Fukui(+)(0.058)数值,说明它们既可以提供电子形成配位键,也可以接受电子形成反馈键。     

Electrochemical investigation of dynamic interfacial processes at 1-octadecanethiol-modified copper electrodes in halide-containing solutions

1-Octadecanethiol (C18SH) monolayers were self-assembled on the fresh and active copper surface pretreated by nitric acid etching method. The surface properties of the alkanethiol-modified copper electrode in halide-containing solutions were characterized systematically by using several electrochemical methods, including polarization curves, cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN). The results show that C18SH self-assembled monolayers (SAMs) onto copper provide a flexible method that can protect the underlying copper against corrosion. With the immersion time of SAMs-coated copper electrode in NaCl and HCl corrosive solutions increasing, a slow loss of corrosion protection ability of SAMs indicates dynamic processes occurring at the electrode/solution interface and in the monolayers, such as expansion of the defects and transport of corrosive ions through defects of SAMs. Electrochemical noise (EN) is employed to detect the alkanethiol-modified copper surfaces immersed in HCl solution. This observation suggests the pitting process associate with dynamic processes in the 1-octadecanethiol layer.     

Spectroelectrochemical study of trichloroacetic acid reduction at copper electrodes in an aqueous sodium sulfate medium

The electrochemical reduction of trichloroacetic acid (TCAA) in water has been analyzed through voltammetric studies with a copper rotating disc electrode supported by controlled-potential bulk electrolysis and electrochemical surface-enhanced Raman spectroscopy (SERS) experiments. The influences of the mass-transport conditions and concentration were studied. It has been pointed out that the electrochemical reduction of trichloroacetic acid takes place prior to the massive hydrogen evolution. Strong adsorption was observed on the electrode surface, and dichloroacetic acid (DCAA), monochloroacetic acid (MCAA), and chloride anions were detected as reduction products. The SERS experiments point to a secondary mechanism in which dissociative adsorption of the trichloroacetic acid gives rise to the adsorption of CO, and therefore, to the production of 1C molecules as by-products of the electrochemical reduction.     

Protection of copper surface in acidic chloride solution by non-toxic thiadiazole derivative

This paper deals with electrochemical properties of copper in the presence of the non-toxic compound 2-amino- 5-ethyl- 1,3,4-thiadiazole (AETDA) in acidic chloride solution. Electrochemical techniques: open circuit potential measurements, linear potentiodynamic measurements, cyclic voltammetry measurements and chronoamperometric measurements in addition to SEM–EDS analysis were used during the work. Results show that inhibition efficiency of 2-amino-5-ethyl-1,3,4-thiadiazole depends on inhibitor concentration and immersion time of copper electrode in inhibitor solution. Cyclic voltammetry and linear potentiodynamic measurements beside chronoamperometric measurements indicate formation of protective layer on copper surface. Moreover, results obtained by electrochemical measurements point out that the stability of formed layer depends primarily on the concentration of inhibitor and of potential values at which protective film is formed. Also, potentiodynamic measurements show that AETDA in acidic chloride solutions acts as mixed-type inhibitor. Inhibition mechanism of 2-amino-5-ethyl-1,3,4-thiadiazole includes adsorption of inhibitor on active sites on electrode surface which was confirmed by SEM–EDS analysis of the electrode surface. Adsorption of the AETDA in HCl solution obeys Langmuir adsorption isotherm.     

Electrochemical assessment of electrochemical oxidation stability of self-assembled monolayers on gold and preparation of binary self-assembled monolayers on gold

Binary thiolates self-assembled monolayers (SAMs) on gold have been prepared efficiently by using an electrochemical oxidation combining with replacement reaction method. The electrochemical results show that both the SAMs of mercaptoacetic acid (MAA) and 1-dodecanethiol (DT) on gold surface are oxidized at certain anodic potentials (noting: it is not oxidative redeposition of alkanethiolate monolayers on gold surface), and the degree of electrochemical oxidation of single thiolates-SAMs is function of the polarization potential and polarization time. Therefore, formation of binary MAA-DT thiolates-SAMs can be achieved if MAA or DT is present in solution after the electrochemical oxidation of DT or MAA SAMs on gold electrode. In this case, the ratio of MAA to DT on the binary thiolates-SAMs can be easily controlled by controlling polarization potential and/or polarization time. The present approach enables us to prepare homogeneously binary SAMs with different composition, and assess the electrochemical oxidation stability of single thiolates-SAMs by means of cyclic voltammetry measurements of redox probe.     

Arginine self-assembled monolayers against copper corrosion and synergistic effect of iodide ion

Self-assembled monolayers (SAMs) of arginine (Arg) were formed on copper surface. The corrosion protection properties of the Arg SAMs were examined by electrochemical impedance spectroscopy and polarization techniques in 0.5 M HCl solution. The results show that Arg SAMs have limited protection effect. The protective efficiency increased with an increase of self-assembly time and reached maximum protection at 6 h. When iodide ion was added to the Arg-containing solution, the ability of the corrosion inhibition of the mixed SAMs improved significantly. The corrosion protection mechanism of Arg SAMs is discussed based on AM1 quantum-chemical calculations.     

Electrodeposition of palladium on the copper lead frame: Electrode reaction characteristics and the effects of primary additives

This study is mainly concerned with the electrodeposition of palladium on the copper alloy lead frame used for semiconductor assembly process. The role and effect of additives on palladium electrodeposition were studied by using various electrochemical methods. Ortho-formylbenzenesulfonic acid as a primary additive was used in palladium plating on the lead frame in this study. The electrochemical characteristics of electrode reaction were measured by the hanging mercury drop electrode for electrochemical system and the qualities of the plated surface of lead frames were also examined. The additive agent in Pd solution could have been classified as the grain refiner. It acted as the electroactive species, which increased the polarization and decreased the roughness, by adsorption on the electrode in palladium pre-plated process. The reduction of palladium ion was identified to be an irreversible reaction and the diffusion coefficient of palladium ion and the reaction rate constant were obtained from chronopotentiometry experiment.     

Surface protection of copper in aerated 3.5% sodium chloride solutions by 3-amino-5-mercapto-1,2,4-triazole as a copper corrosion inhibitor

Surface protection of copper in aerated 3.5% NaCl solutions by 3-amino-5-mercapto-1,2,4-triazole (AMTA) has been reported. The study has been carried out using weight loss, pH, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and chronoamperometric (CA) measurements along with scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) investigations. Weight-loss data indicated that the dissolution rate and the pH of the solution decreased to a minimum after 24 days of copper immersion due to the inhibitive action of AMTA. PDP, CA, and EIS measurements showed that AMTA decreased the corrosion rates and increased the polarization resistance and inhibition efficiency. This effect was increased with increasing AMTA concentration as well as the immersion time of the copper electrode to 50 h before measurements. SEM micrograph and EDS analysis proved that the inhibition of copper corrosion takes place due to adsorption of AMTA onto the surface. These results together confirmed that AMTA is a good mixed-type inhibitor and the inhibition of copper corrosion is achieved by strong adsorption of AMTA molecules.     

Anticorrosive coating based on poly(vinyl acetate) formed by electropolymerization on the copper surface

The poly(vinyl acetate) (PVAC) film was obtained by electropolymerization on the copper electrode using cyclic voltammetry performed in mixed electrolyte based on water/ethyl alcohol/acetic acid containing vinyl acetate (VAc) and benzoyl peroxide as polymerization initiator. The coatings were characterized by optical microscopy, scanning electron microscopy (SEM) and infrared (IR) spectroscopy. The corrosion was induced in hydrochloric acid solution using potentiodynamic measurements and electrochemical impedance spectroscopy (EIS). The microscopic and SEM images revealed the PVAC coating formation and IR spectroscopy confirmed that it exhibits the same characteristic bands as a standard PVAC sample. From the potentiodynamic polarization, the PVAC protective performance of 78% was computed. The EIS measurements showed the occurrence of the surface adsorbed layer with a higher impedance response to the frequency and a phase angle maximum shifted to lower values than those of uncoated samples. In addition, the VAc electropolymerization mechanism was discussed and the PVAC adsorption mechanism on the copper surface was proposed. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47320.