Deposition from aqueous alcohol solutions is the most facile method for preparing silylated surfaces. A 95% ethanol / 5% water solution is adjusted to pH 4.5–5.5 with acetic acid. Silane is added with stirring to yield a 2% final concentration. Five minutes should be allowed for hydrolysis and silanol formation. Large objects, e.g. glass plates, are dipped into the solution, agitated gently, and removed after 1–2 minutes. They are rinsed free of excess materials by dipping briefly in ethanol. Particles, e.g. fillers and supports, are silylated by stirring them in

solution for 2–3 minutes and then decanting the solution. The particles are usually rinsed twice briefly with ethanol. Cure of the silane layer is for 5–10 minutes at 110°C or 24 hours at room temperature (60% relative humidity).

For aminofunctional silanes such as SIA0610.0 and SIA0589.0 this procedure is modified by omitting the addition of acetic acid. The procedure is not acceptable for chlorosilanes as bulk polymerization often occurs. Silane concentration of 2% is a starting point. It usually results in deposition of trialkoxysilanes as 3–8 molecular layers. Monoalkoxysilanes are always deposited as monolayers or incomplete monolayers. Caution must be exercised if oven curing. Exhausted,explosion-proof ovens must always be used.

Deposition from aqueous solution is employed for most commercial fiberglass systems. The alkoxysilane is dissolved at 0.5–2.0% concentration in water. For less soluble silanes, 0.1% of a non-ionic surfactant is added prior to the silane and an emulsion rather than a solution is prepared. If the silane does not contain an amine group the solution is adjusted to pH 5.5 with acetic acid. The solution is either sprayed onto the substrate or employed as a bath dip. Cure is at 110–120°C for 20–30 minutes.