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硅醇分子与氧化铝表面键合的DFT研究

A DFT Study of the Bonding of Silanol Molecules to Oxidized Aluminum Surfaces
课程网址: http://videolectures.net/ipssc2017_poberznik_oxidized_aluminum_su...  
主讲教师: Matic Poberžnik
开课单位: 约瑟夫·斯特凡研究所
开课时间: 2017-05-23
课程语种: 英语
中文简介:
一种最有前途的新型耐腐蚀涂层,用于保护铝及其合金,是混合溶胶-凝胶涂层,它结合了有机和无机材料的特性。由于传统的高性能铬酸盐转化膜有毒且致癌,因此需要新型涂层。合成杂化溶胶-凝胶涂层的前体之一是硅醇分子,假设它们主要通过冷凝机制与表面反应,如图1a[1,2]所示。为了阐明成键的原子机理,在密度泛函理论(DFT)框架内研究了简单硅醇分子(甲基硅三醇)与固体/真空界面氧化铝表面模型的相互作用利用周期边界条件和PBE交换关联泛函。将气相中两种甲基硅三醇之间的缩合反应(图1b)与分子与氧化表面之间的缩合反应(图1a)进行比较。根据计算,两种反应能都是放热的。分子与表面的反应放热增加约0.2 eV,表明分子与表面之间的键略强于硅醇分子之间的键。因此,我们的计算表明,目前提出的硅醇-表面键合机制在物理上是合理的。
课程简介: One of the most promising novel corrosion resistant coatings, used for the protection of aluminum and its alloys, are hybrid sol-gel coatings, which combine the properties of organic and inorganic materials. Novel coatings are needed because traditional high-performance chromate conversion coatings are toxic and cancerogenic. One of the precursors for the synthesis of hybrid sol-gel coatings are silanol molecules and it is assumed that they react with the surface primarily via a condensation mechanism, as shown in figure 1a [1,2]. To shed some new light on the atomistic mechanism of bonding, the interactions of a simple silanol molecule (methylsilanetriol) with a model of the oxidized aluminum surface at the solid/vacuum interface, were studied within the framework of Density Functional Theory (DFT) utilizing periodic boundary conditions and the PBE exchange-correlation functional. The condensation reaction between two methylsilanetriols in the gas-phase (Figure 1b) was compared to the condensation reaction between the molecule and the oxidized surface (Figure 1a). According to the calculations both reaction energies are exothermic. The reaction of the molecule with the surface is by about 0.2 eV more exothermic, indicating that the bond between the molecule and the surface is slightly stronger than the bond between the silanol molecules themselves. Our calculations thus show that the currently proposed silanol–surface bonding mechanism is physically sound.
关 键 词: 新型耐腐蚀涂层; 有机和无机材料; 硅醇分子
课程来源: 视频讲座网
数据采集: 2021-11-07:zkj
最后编审: 2021-11-07:zkj
阅读次数: 76