Rotaxane functionalized acid-terminated self-assembled siloxane monolayers on non-conducting surfaces - XPS, AFM and TRF

Mechanically interlocked molecules such as rotaxanes are fascinating for their potential in molecular-scale devices. Rotaxane, stimuli-responsive "molecular shuttles" are molecules where a macrocyclic `bead' is locked onto a linear "thread" by bulky "stoppers". Large amplitude motion of the macrocycle can be induced by external stimuli (e.g. light, electrons, heat, pH, polarity of the environment etc.). While the solution chemistry of rotaxanes has been explored extensively, the study of the surface chemistry of these species has been limited to a few examples. Here we report detailed direct information on the surface morphology and the packing of rotaxane on self-assembled monolayer on quartz and silicon oxide/Si(110) followed by the photophysical studies.