【摘要】 从Helmholtz模型出发,对生长在金表面不同链长烷基硫醇自组装单分子膜(SAM)表面电势的变化规律进行了理论研究.利用量子化学软件Gaussian03和MOPAC,讨论了分子偶极矩、相对介电常数以及分子的倾斜角对SAM表面电势的影响.研究表明,不同链长烷基硫醇SAM中分子的倾斜角随烷基链长度的规律性变化是引起SAM表面电势变化的主要原因.从SAM形成机制出发,对金表面不同链长烷基硫醇SAM表面电势的变化规律及其成因提出了新的解释.更多还原

【Abstract】 A theoretical study on the surface potential of alkanethiol self-assembled monolayers (SAMs) with different alkyl chain lengths on a gold substrate was carried out in terms of the Helmholtz model. The influences of molecular dipole moment, relative permittivity of the SAMs, and angle between the molecular chain and the substrate normal on the surface potential were systematically investigated using quantum chemical softwares Gaussian 03 and MOPAC. We found that the variation of surface potentials for the alkanethiol SAMs with different alkyl chain lengths mainly resulted from regular changes in the angles between the molecular chains and the substrate normal. We propose a new explanation for the variation in surface potentials of the alkanethiol SAMs with different alkyl chain lengths by considering the SAM formation mechanism.更多还原