The study of ordered molecular assemblies on inorganic surfaces has been a popular area of research recently because of the applications in biotechnology and sensors. Alkanethiols on the gold surface are the most common approach for making organic films (self-assembled monolayers, SAMs). To have more control over the structure and properties of the surface, more than one type of molecule can be adsorbed on the surface, making a multicomponent SAM. Typically, this is done through coadsorption, which means that the gold surface is subjected to the different molecules at the same time. Alkyl thiocyanates (R-SCN) interact with the gold surface differently than alkanethiols and provide another way of tuning surface properties. Here we use decyl thiocyanate and octanethiol and modify coadsorption deposition parameters such as temperature, exposure time, and concentration to better understand how thiocyanates attach to the surface in comparison to thiols. Scanning tunneling microscopy (STM) is used to characterize the surface at a molecular level to assess the spatial distribution of the molecules on the surface. As the solution concentration of the decyl thiocyanate increases, relative to the octanethiol, there is an increase in its presence on the surface. As the overall concentration decreases, the resulting surface shows more rearrangement of the octanethiol SAM. This research helps expand the methods of forming multicomponent SAMs to help fine-tune the properties of the surface.

Mixed self-assembled monolayers formed through the coadsorption of decylthiocyanate and octanethiol on Au(III) surfaces

253rd National Meeting (2017)

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