Atomic force microscopy imaging of thin films formed by hydrophobing reagents

The hydrophobic films produced on silica plates by a common silylating reagent, trimethylchlorosilane, at the solid/liquid and solid/gas interfaces have been imaged directly using an atomic force microscope. The results obtained here support previous findings that such reactants produce relatively thick inhomogeneous films. For the first time we are able to present direct images of the spatial inhomogeneity of such films. The thin film produced by esterification of the silica plates with 1-dodecanol has also been imaged. In this case, a good, post-reaction, cleanup procedure was determined to be vital in obtaining a uniform thin hydrophobic film. Comparison with a previous ellipsometric study from this laboratory shows broad agreement on the observed film thicknesses and homogeneities for all samples.