Self-assembly of alkanethiol molecules onto platinum and platinum oxide surfaces
Self-assembly of alkanethiol molecules onto platinum and platinum oxide surfaces
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DOI：
10.1021/la034245b
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发表时间：
2003-08-19
期刊：
影响因子：
3.9
通讯作者：
Williams, RS
中科院分区：
文献类型：
--
作者：
Li, ZY;Chang, SC;Williams, RS
研究了正硫醇CH3(CH2)(M)SH(m=5，7，9，11，13，15，17，19，21)在金属和氧化物两种不同表面性质的铂薄膜上的自组装行为。水接触角、椭偏仪和反射吸收红外光谱(RAIRS)的测量表明，在金属铂表面形成了有序的、甲基封端的单分子膜。另一方面，烷基硫醇分子在铂氧化物表面形成的分子膜排列疏松，有序性差。对于不同链长的烷基硫醇在金属铂表面形成的单分子膜，随着链长的增加，从轻微的无序结构向类晶态结构转变。根据RAIRS中次甲基和甲基C-H振动模式的强度，估算了铂表面单分子膜中烷基链相对于表面法线的倾斜角小于15°。X-射线光电子能谱表明，烷基硫醇分子中的硫醇头基与表面的铂原子形成了金属-硫代键。
We studied the self-assembly of n-alkanethiols CH3(CH2)(m)SH (m = 5, 7, 9, 11, 13, 15, 17, 19, 2 1) onto platinum thin films with two different surface properties: metallic and oxide. Water contact angle, ellipsometry, and reflection-absorption infrared spectroscopy (RAIRS) measurements suggested that well-organized, methyl-terminated monolayer films formed on the metallic platinum surface. On the other hand, the molecular films formed with the alkanethiol molecules on platinum oxide surfaces were loosely packed and poorly ordered. For the monolayer films formed with alkanethiols of different chain lengths on metallic Pt surfaces, a transition from slightly disordered to crystalline-like structure was observed with increasing chain length. Based on the intensities of the methylene and methyl C-H vibration modes in the RAIRS, the tilt angle of the alkyl chain in the monolayers on Pt surfaces was estimated to be less than 15degrees with respect to the surface normal. X-ray photoelectron spectroscopy revealed the formation of metal-thiolate bonding of the thiol headgroups in the alkanethiol molecules with Pt atoms on the surfaces.