Phase separation in class II organically modified silicate films as probed by phase-imaging atomic force microscopy

Phase imaging tapping mode atomic force microscopy has been used to examine the presence and extent of phase separation in organically modified silicate films. A total of seven films were prepared using two different synthetic routes (cohydrolysis/condensation and separate hydrolysis/condensation) with three different organoalkoxysilanes and tetraethoxysilane. Films made from separately hydrolyzed sols were rougher and had larger phase separated domains compared to films prepared from cohydrolyzed sols. Likewise, films prepared from sols containing organoalkoxysilanes with nonpolar bulky substituents, such as ethyl and isobutyl, were significantly rougher and more phase separated relative to those prepared from a more miscible nitrile alkoxysilane.