(471f) Guest Instercalation and Regeneration in Low-Density Self-Assembled Monolayers

We have synthesized thiol-based low-density self-assembled monolayer (SAM) structures in which cavities are formed via the introduction of a bulky spacer group. Structurally homologous guest molecules consisting of functional groups with pendant alkane tails can be intercalated into the cavities between hydrophobe arrays at the liquid-solid interface from solution under well-controlled conditions, offering the potential ability to separate the surface functionality of the monolayer from the inherent structure of the host.   Self-assembled monolayers of (10-octadecyl)-9-anthracenethiol (host-SAMs) were prepared on Au substrates. Quartz crystal microbalance with dissipation (QCM-D) measurements were used to demonstrate the capacity of LDSAMs to confine guest molecules in the cavities and to probe the structural changes of the host-guest assembly during guest intercalation from ethanol solutions. X-ray photoelectron spectroscopy (XPS) measurements were then used to probe host-guest monolayers formed by immersion of the host monolayers in guest solutions in a variety of other solvents. The results demonstrate that guest molecules were intercalated into host-cavities and that the reversibility of the intercalation process allows a guest already present in a host-cavity to be replaced with second guest under well-regulated solution conditions.