TEMPERATURE INFLUENCE ON THE FORMATION OF SILANIZED MONOLAYERS ON SILICA - AN ATOMIC-FORCE MICROSCOPY STUDY

We observed stages in the formation of self assembled n-octadecyltrich lorosilane monolayers on silicon wafers using atomic force microscopy, At low temperature, the surface is first covered by a disordered phas e, comparable to the liquid expanded phase of Langmuir films, Further addition of molecules causes reorganisation into a thicker and more or dered phase, similar to the liquid condensed phase of a Langmuir film. Both phases are formed through a first order transition. At high temp erature, we find only the liquid expanded phase and a very different p rocess for the monolayer formation.