ganic hybrid layered materials have been reported by Fukus-A 2:1 smectite-type clay containing thiol groups on a basal plane hima and Tani (8). According to them, silyl reagents were was synthesized by reacting magnesium chloride with mercaptoreacted with magnesium chloride in an aqueous alkaline suspropyltrimethoxysilane in an alkaline methanol/water mixture. pension at room temperature to produce smectite-type clay The material (denoted as an HS-Mg layer) was identified by elematerials.
mental analyses and X-ray diffraction measurements. The HS-Mg
In this paper, we report the preparation of a clay conlayer was revealed to be self-assembled on a gold surface. The taining thiol groups on a basal surface according to the modiprocess was confirmed by monitoring the increase in mass of a fied method. Such a clay has been revealed to be self-assemgold electrode with a quartz crystal microbalance when the elecbled on a gold surface. The process was followed by the trode was immersed in a chloroform dispersion of the HS-Mg layer. Nanoscale images of a gold surface treated with the HS-Mg increase in mass of a gold electrode with the quartz crystal layer were obtained by atomic force microscopy. The 400 1 400microbalance (QCM). The surface structure of a gold crystal nm image of the sample showed that the surface was covered with treated with the clay was investigated by atomic force miplatelets of about 30 nm in diameter and 1.9 nm in thickness. The croscopy (AFM). In comparison to the reported multilayer 3.00 1 3.00-nm image showed that the bright spots on the surface formations of inorganic compounds (9, 10), the present sysof the particle displayed periodicity. The spots were ascribed to tem is characterized by the following aspects: (1) the coverthe alkanethiol groups on the silicate sheet of the HS-Mg layer. age of a self-assembled monolayer is controlled by changing
The observed periodicity coincided with the tetrahedral sheet of reaction time; (2) the thiol groups on the external surface of a model smectite clay.