MOLECULAR-CONFORMATION AND NANOMECHANICS OF SELF-ASSEMBLED ALKYLSILOXANE MONOLAYERS

We have studied the chain conformation and nanomechanical properties o f pure alkylsiloxane monolayers and the mixed films with fluorine-cont aining species using scanning force microscopy (SFM) and infrared-visi ble sum-frequency generation spectroscopy (IV-SFG). Our IV-SFG spectra yield information about the chain ordering and surface density of spe cific species in the pure and mixed monolayers. A film formation proce ss involving preferential adsorption of the fluorinated species from s olution was observed. On the basis of the SFM measurements, the stiffn ess of alkylsiloxane monolayers under load was found to increase with the chain length, changes of chain conformation, and alkyl chain fluor ination.