Es. Franklin et al., DETERMINATION OF THE EFFECTS OF A BIPOLAR POLYPYRIDYLOSMIUM(II) COMPLEX ON THE STABILITY OF MONTMORILLONITE COLLOIDS, Journal of colloid and interface science (Print), 204(1), 1998, pp. 157-168
Adsorption of a large cationic complex on the surface of a montmorillo
nite colloid results in flocculation of the colloid. This destabilizat
ion of the colloid does not occur when the cationic complex has been m
odified to contain a side-chain terminating in an anionic group (i.e.,
the complex is bipolar). The influence of such a bipolar complex on t
he particle sizes in montmorillonite colloids was examined using a pol
ypyridylosmium(II) complex. Laser Doppler velocimetry was employed to
determine the particle-size distributions in montmorillonite colloids
containing various concentrations of the osmium complex and 1.00 g L-1
of clay. At loadings below the cation-exchange capacity of the clay,
the particle-size distribution was independent of the total concentrat
ion of the bipolar osmium(II) complex. Under these conditions, at leas
t 98% of the complex was adsorbed on the clay. (C) 1998 Academic Press