【作者】 伍廉奎；

【导师】 胡吉明；

【作者基本信息】 浙江大学 ， 化学， 2014， 博士

【摘要】 硅烷sol-gel材料在金属腐蚀防护、光学及光催化材料、电分析和生物传感器等领域有着广泛应用。传统浸涂或旋涂法制备硅烷sol-gel薄膜过程中,受成膜动力学的限制,得到的薄膜较薄、可调控性差。基于阴极局部碱化促进硅烷sol-gel成膜的电沉积法的引入,有效地解决了这个问题。目前,电沉积硅烷sol-gel薄膜的研究主要侧重于电分析和生物传感器材料的制备。本论文中,研究了硅烷sol-gel薄膜电沉积过程中若干基础问题,在此基础上成功制备得到了具有梯度结构的sol-gel薄膜；提出采用一步电沉积技术制备金属锌掺杂的硅烷膜和硅烷掺杂的电泳漆涂层用于金属防护；提出以电沉积无机Si02为模板制备电催化活性提高的多孔薄膜材料；采用两步法或一步法实现了电沉积sol-gel薄膜的超疏水化,拓展了电沉积硅烷sol-gel薄膜的应用。本论文主要研究工作包括：(1)研究了电沉积sol-gel薄膜的若干基础问题。采用EQCM原位监测电沉积硅烷sol-gel薄膜成膜过程,提出了硅烷sol-gel成膜过程分为“诱导成膜期”——慢速生长期——快速生长期三个步骤,其中“诱导成膜期”的长短取决于施加的电极电位。理论计算发现,不同电位下,薄膜开始形成时电极表面pH均在9.8左右,而薄膜的孔隙率随沉积电位负移而增大。气体吸脱附实验表明沉积电位越负,所得薄膜的比表面积越小,而荧光染料吸附试验表明,沉积电位越负,所得sol-gel薄膜的吸附能力越强。在此基础上,提出并实现了电沉积制备具有横向梯度结构的硅烷sol-gel薄膜。(2)硅烷电沉积在金属防护中的应用。主要包括两个方面：一、利用阴极电位下,前驱体中锌离子发生还原生成金属锌单质；同时,H2O、O2或N03-离子还原生成的OH-可提高阴极局部pH,促进硅烷成膜,从而实现一步电化学共沉积制备金属锌掺杂的硅烷膜。EIS、开路电位、湿热试验及铁离子溶出实验均表明,掺杂金属锌可提高硅烷膜的耐蚀性能,XPS确定了复合膜中锌以金属锌单质的形态存在。二、利用阳离子环氧树脂和硅烷均可在阴极电位下成膜的共同点,一步阴极电泳沉积构建硅烷掺杂的电泳漆“超级涂层”用于镀锌钢的腐蚀防护。EIS测试表明,掺杂少量硅烷(0.3wt.%BTSE或0.5wt.%MTMS)可显著提高电泳漆涂层的耐蚀性能,降低涂层的吸水率,提高涂层的机械性能和疏水性,FTIR测试表明掺杂的硅烷组分可在金属/涂层界面优先富集,起到提高涂层与基体结合力的作用。(3)电沉积SiO2模板技术在纳米多孔电极材料制备中的应用。首先,一步电沉积制备SiO2/Ni或SiO2/Co3O4复合膜,然后,在KOH溶液中经过循环伏安处理,得到多孔Ni或多孔Co3O4薄膜。SEM和TEM测试表明,以SiO2为模板制备的Ni或Co3O4薄膜多孔性增大,FTIR, EDX点能谱和面能谱证明碱液中循环伏安处理可有效去除复合膜中的SiO2组分,电化学测试(LSV和CV)表明采用该法制备的多孔Ni和多孔Co3O4薄膜电极用于超级电容器及碱性和中性环境下析氧阳极时电催化活性均显著提高。(4)电沉积超疏水sol-gel薄膜及其性能研究。主要包括两个方面：一、利用电沉积无机SiO2薄膜高度粗糙多孔的性质,结合长链烷基硅氧烷良好疏水性的特点,采用两步法制备得到了超疏水siO2薄膜。SEM图片和表面轮廓仪测试表明改变沉积时间和施加电位,可有效调控薄膜的厚度、粗糙度及疏水性。此外,还研究了基体和表面活性剂对超疏水SiO2薄膜的影响。二、一步电沉积制备超疏水有机硅烷sol-gel薄膜和无机-有机复合硅烷sol-gel薄膜。无机SiO2组分的引入可有效提高超疏水薄膜的热稳定性、酸碱稳定性和机械强度。更多还原

【Abstract】 Silane sol-gel materials have been widely used in corrosion protection of metal, optical and photocatalytic materials, electroanalysis and biosensors, etc. Due to the limited by the dynamics for the formation of silane films, the dip-coated and spin-coated films are very thin and poor in regulating. The novel electrodeposition method, which is based on the facilitation of silane sol-gel film by cathodic generated OH-ions, effectively solved this problem. Nowadays, the research on electrodeposited silane sol-gel films are mainly focused on electroanalysis and biosensors. In this thesis, some fundamental issues in the electrodeposition of silane sol-gel films were investigated. Based on this, gradient sol-gel films were fabricated. One-step preparation of zinc doped silane films and silane incorporated electrophoretic coating were proposed for the corrosion protection of metals. Porous functional film materials based on electrodeposited SiO2as template were proposed. And superhydrophobic sol-gel films have been fabricated via two-step or one-step, which expanded the application of electrodeposited silane sol-gel films. The main contents are listed as follows:(1) Some fundamental issues in the electrodeposition of silane sol-gel films wereinvestigated. EQCM was used for in-situ monitoring the deposition process of silane sol-gel film. We divided the formation of silane sol-gel film into three stages:the introduction of film formation stage, low growing rate stage and faster gelification stage. The period of the introduction of film formation stage is dependent on the applied potentials. Theoretic calculation results show that the sol-gel films can be generated when the pH near the electrode surface reached to～9.8, and the porosity of the film increases with the deposition potential shift negatively. N2absorption and desorption test indicates that the more negative potential applied, the smaller of the specific surface area of the films. While fluorescent dye adsorption test results show that more dye would be loaded on the films prepared at more negative potentials. Based on the results, gradient silane sol-gel films were fabricated.(2) Silane electrodeposition for the corrosion protection of metals. Firstly, based on the doped zinc ions in the precursor would be reduced to zinc under cathodic potential, and the generated OH-ions due to the reduction of H2O, O2and/or NO3-could facilitate the formation of silane films, zinc-doped silane films were fabricated via one-step electrodeposition. EIS, open circuit potential, wet heat test and iron ions dissolving test show that the corrosion protection property would be enhanced due to the doped zinc. XPS further indicates the existence of metallic zinc in the hybrid films. Secondly, based on both cationic epoxy resin and silane film could be formed under cathodic potential, silane incorporated electrophoretic coating were fabricated via one-step for the corrosion protection of galvanized steel. EIS test results show that the incorporation of tiny amount silane (0.3wt.%BTSE or0.5wt.%MTMS) could significantly enhance the corrosion protection property, reduce water uptake, improve hydrophobicity and mechanical property of the coating. FITR further indicates the silane-enriched layer preferentially formed on the metal/coating interface could improve the adhesion between the coating and substrate.(3) Electrodeposition of SiO2template technology and its application in the preparation of nano-porous materials. Firstly, the preparation of electrocatalytic activity enhanced porous films based on electrodeposited SiO2as templates. At first, one-step electrodeposition of SiO2/Ni or SiO2/Co3O4hybrid films, then porous Ni or Co3O4films could be formed by consecutive CV scans in KOH solution. SEM and TEM indicate the the porosity of the obtained Ni or Co3O4films are improved. FTIR and EDX show that the silica component could be removed completely by repeated CV scans in KOH solution. Electrochemical test (CV and LSV) demonstrate that the electrocatalytic activity and specific capacity of these porous Ni or Co3O4films are obviously improved.(4) Electrodeposition of superhydrophobic sol-gel films and the study of its performance. Firstly, the fabrication of superhydrophobic sol-gel films based on the highly porous E-SiO2film and environmental friendly hydrophobic alkoxysilane via two-step. SEM images and profiler tests show the thickness, roughness and hydrophobicity of the sol-gel films could be regulated easily by altering the electrolysis time and applied potential. What’s more, the influence of substrate and surfactant on the superhydrophobic films are also investigated. Secondly, one-step fabrication of superhydrophobic organic silane films and inorganic and organic hybrid silane films. It is found that the thermal stability, chemical stability and mechanical strength of the superhydrophobic films can be significantly improved due to the introduction of inorganic SiO2component.更多还原