Structure of an adsorbed polyelectrolyte monolayer on oppositely charged colloidal particles.
An adsorbed layer of a cationic polyelectrolyte, poly(diallyldimethyl-ammonium) chloride (PDADMAC) on negatively charged colloidal latex particles was investigated by small-angle neutron scattering (SANS) and dynamic light scattering (DLS). SANS gives a layer thickness of 8 +/- 1 A and a polymer volume fraction of 0.31 +/- 0.05 within the film. DLS gives a somewhat larger thickness of 18 +/- 2 A, and the discrepancy is likely due to the inhomogeneous nature of the layer and the existence of polymer tails or loops protruding into solution. These results show that a highly charged polyelectrolyte adsorbs on an oppositely charged colloidal particle in a flat configuration due to the attractive forces acting between the polyelectrolyte and the substrate.
Vaccaro
Andrea
A
Department of Inorganic, Analytical, and Applied Chemistry, University of Geneva, 1211 Geneva 4, Switzerland.
Hierrezuelo
José
J
Skarba
Michal
M
Galletto
Paolo
P
Kleimann
Jörg
J
Borkovec
Michal
M