How to Modify Interparticle Forces and Colloidal Stability by Adsorbed Polyelectrolytes

Adatlap
Előadó: 
Michal Borkovec (Department of Inorganic and Analytical Chemistry, University of Geneva)
Időpont: 
ked., 2013-05-28 16:15
Helyszín: 
0.100A terem

Polyelectrolytes strongly influence colloidal stability or particle deposition processes, and this mechanism is highly relevant in waste water treatment, papermaking, and the development of advanced materials. Only recently, knowledge started to accumulate concerning the structure of adsorbed polyelectrolyte layers on oppositely charged surfaces and the resulting surface forces. Principal findings are that adsorbing polyelectrolyte lead to charge reversal and that the resulting layers are laterally heterogeneous and very thin (typically few nanometers). Interactions between these layers are principally controlled by electrostatic double-layer and van der Waals forces as described by the theory of Derjaguin, Landau, Verwey and Overbeek (DLVO). However, additional attractive non-DLVO forces are present, which are induced by lateral heterogeneities in the surface charge distribution (patch-charge attraction). The talk will focus on these recent developments and also highlight relevant state-of-the-art of experimental techniques (i.e., light scattering, reflectivity, quartz crystal microbalance, and atomic force microscopy).