Adsorption of PVA on kaolin pre-adsorbed with CPC (CPC+PVA mode) is also shown Figure 1. The
maximum adsorption of PVA on bare kaolin is 0.30 mg/m2 which agrees with previous findings by
Sjöberg, et.al [12] and Backfolk et.al.[21]. These researchers reported an apparent adsorption plateau of
PVA on kaolin of about 0.3 - 0.5 mg/m2
at pH 8.5-9 depending on the source of the kaolin. The apparent
adsorption plateau of PVA decreases to 0.25 mg/m2
, when CPC is pre-adsorbed on the kaolin particles.
It has been found that ionic surfactants and PVA molecules can form complexes under certain conditions
[35,36]. It is possible that the association between the polymer and surfactants and complex formation in
the solution phase or at the surface is the cause of the change of adsorbed amount of PVA when either of
the surfactants has been pre adsorbed.