SAMs on Gold Derived from Adsorbates Having Phenyl and Cyclohexyl Tail Groups Mixed with Their Phase-Incompatible Fluorinated Analogues
SAMs on Gold Derived from Adsorbates Having Phenyl and Cyclohexyl Tail Groups Mixed with Their Phase-Incompatible Fluorinated Analogues
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DOI：
10.1021/acs.langmuir.2c01991
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发表时间：
2022-10-26
期刊：
影响因子：
3.9
通讯作者：
Lee，T. Randall
中科院分区：
文献类型：
--
作者：
Yu，Tianlang;Marquez，Maria D.;Lee，T. Randall
本文研究了两种类型的混合自组装单分子膜（SAMs）衍生自具有环己基和苯基尾部基团的吸附物与它们的全氟类似物混合。采用椭圆偏振光谱仪、X射线光电子能谱（XPS）、偏振调制红外反射吸收光谱和接触角测量对混合自组装膜进行了表征。XPS结果表明，由于尾基的空间体积，全氟环己基封端/环己基封端对中的非氟化吸附物优先吸附。另一方面，实现了精确控制的表面组成的混合表面与苯基封端/全氟苯基封端的混合自组装膜，表现出的表面上的摩尔分数和溶液中的摩尔分数之间的线性关系。结果表明，相对溶解度、尾基部分的空间体积以及两种不同吸附物之间的相互作用是导致自组装膜中观察到的相现象的关键因素。更重要的是，这项研究表明，界面性能可以控制与苯基封端/全氟苯基封端的混合自组装膜的堆积密度的最小损失。
This article investigates two types of mixed self-assembled monolayers (SAMs) derived from adsorbates having cyclohexyl and phenyl tail groups mixed with their perfluorinated analogues. The mixed SAMs were characterized using ellipsometry, X-ray photoelectron spectroscopy (XPS), polarization–modulation infrared reflection absorption spectroscopy, and contact angle measurements. The XPS results show preferential adsorption of the nonfluorinated adsorbate in the perfluorocyclohexyl-terminated/cyclohexyl-terminated pair due to the steric bulk of the tail groups. On the other hand, mixed surfaces with a precisely controlled surface composition were achieved with the phenyl-terminated/perfluorophenyl-terminated mixed SAMs, exhibiting a linear relationship between the mole fraction on the surface and the mole fraction in solution. The results suggest that the relative solubility, steric bulk of the tail group moiety, and the interaction between two different adsorbates are the key factors driving the phase phenomena observed in the SAMs. More importantly, this study suggests that the interfacial properties can be controlled with a minimal loss of packing densities with the phenyl-terminated/perfluorophenyl-terminated mixed SAMs.