(520e) Low-Density Self-Assembled Monolayers for Functional Host-Guest Thin Films

We have investigated
the exchange of functional guest molecules for tunable surfaces with host-guest
thin film systems. Self-assembled host-monolayers containing pre-existing
cavities have been prepared on a quartz-crystal or gold substrate via a
stepwise reaction. The host-monolayers consist of an integrated spacer, usually
aromatic group such as anthracene-derivatives, at the base of the cavity. Guest molecules consisting of a functional
moiety and a long alkane tail can be then inserted into the host-cavities in order to form functionalized surfaces. The insertion and
replacement processes of guest molecules from an organic solution into the
host-cavities have been measured using quartz crystal microbalance with
dissipation monitoring, QCM-D. In addition to the frequency (mass) change of
inserted quest molecules, changes in the film structure upon guest insertion
was also obtained via X-ray reflectivity. The resultant host-guest thin films
were also characterized by contact angle measurements, Fourier Transform
infrared spectroscopy, and X-ray photoelectron spectroscopy.