The time-dependent adsorption of propyltrimethoxysilane (PTMS) in aqueous solution on four substrates (aluminum, zinc, iron and chromium oxide) has been investigated using x-ray photoelectron spectroscopy. Oscillations in the adsorption isotherm as a function of adsorption time in solution have been observed for all of the substrates studied. The adsorption of PTMS is shown to depend strongly upon the isoelectric point of the surface oxide. The closer the isoelectric point is to the solution pH, the more rapid is the initial adsorption rate of silane on the surface. Models are proposed to explain the influence that the electrokinetics of the surface has upon the adsorption mechanism.
|Number of pages||4|
|Journal||Surface and Interface Analysis|
|Publication status||Published - Aug 1999|