ULTRATHIN LIQUID-FILMS - ELLIPSOMETRIC STUDY AND AFM PRELIMINARY INVESTIGATIONS

Films of molecular thickness exhibit a large variability, both in thei r structural properties and in their spreading dynamics. The thickness profiles of nonvolatile liquid microdroplets spreading spontaneously on smooth solid surfaces provide information on short range liquid-liq uid and liquid-solid interactions. These profiles can in principle be recorded by various techniques, including spatially resolved ellipsome try and atomic force microscopy (AFM). The main part of the paper deal s with results obtained using ellipsometry. In particular, the influen ce of water adsorbed on the substrate on the spreading dynamics of var ious liquids is reported. Unexpected problems met with the AFM techniq ue are discussed, further work is under way.