We have directly imaged n-alkane layers adsorbed at the liquid/graphite interface using a scanning tunneling microscope. The layers possessed a high degree of two-dimensional ordering. The adsorbate was observed to enhance the tunneling current, and the atomic structure of the images was dominated by features associated with the substrate. These systems are excellent vehicles for studies concerning the imaging mechanism of adsorbed organic layers because of their stability and simplicity.

We have directly imaged n-alkane and n-alkanol layers at the liquid–graphite interface using a scanning tunneling microscope (STM). The layers possessed a high degree of two-dimensional ordering, and the adsorbate was observed to enhance the tunneling current. The results of this study agree with calorimetric and surface mass measurements, and show that these macroscopic measurements can aid in the selection of systems suitable for imaging with the STM.

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. Tliis monolayer phase transition may proceed via a rotator phase similar to those observed in solid 1-alkanols at higher temperature.The formation of a physisorbed organic monolayer on solid surfaces has been a subject of great interest because of its importance in relation to processes such as adhesion, lubrication, corrosion, and adsorption. Using the scanning tunneling microscope (STM), we have previously observed the formation of a highly ordered n-alkane monolayer physisorbed at the liquid/graphite interface.12 To explore further the interesting phenomena of molecular ordering at the liquid/solid interface, we have examined the adsorption of 1-dodecanol [CH3(CH2)ioCH20H] on a

No abstract

No abstract