STRUCTURAL PHASE-TRANSITION OF A 1-DODECANOL MONOLAYER PHYSISORBED AT THE LIQUID GRAPHITE INTERFACE BY SCANNING TUNNELING MICROSCOPY

The adsorption of a 1-dodecanol monolayer at the liquid/graphite interface was investigated using the scanning tunneling microscope. Two distinct adsorbed structures were observed between the bulk 1-dodecanol melting temperature (297 K) and the adsorbed layer melting temperature (333 K). The molecular packing arrangement shows a herringbone structure at 303 and 308 K, while at 313 K the monolayer exhibits a structure similar to that of the bulk crystal of 1-dodecanol. This monolayer phase transition may proceed via a rotator phase similar to those observed in solid 1-alkanols at higher temperature.