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-octadecyltrichlorosilane monolayers on silicon wafers using atomic force microscopy, At low temperature, the surface is first covered by a disordered phase, comparable to the liquid expanded phase of Langmuir films, Further addition of molecules causes reorganisation into a thicker and more ordered phase, similar to the liquid condensed phase of a Langmuir film. Both phases are formed through a first order transition. At high temperature, we find only the liquid expanded phase and a very different process for the monolayer formation.