Deposition of colloidal particles in monolayers and multilayers

Abstract

Preliminary observations are reported on the deposition of alumina, silica, zinc sulfide and gold colloidal particles on solid surfaces. The alumina, which is positively charged, can induce subsequent deposition of the other colloids (which are negative) onto glass, as pointed out by Iler in 1966. However, more uniform, reproducible and rapid deposition occurs on two monolayers of docosylamine sulfate applied to the glass by the Langmuir-Blodgett technique. The zinc sulfide sol, which is not stable to flocculation, deposits as three-dimensional aggregates. The deposition of colloidal gold was followed by optical absorption measurements, and layers containing a substantial fraction of the close-packed limit were obtained.