96 Aristeidis Papagiannopoulos and Stergios Pispas
Polyelectrolyte/surfactant complexes were tested against dilution with
water. The presence of hydrophobic nano-domains inside the complexes
decreases gradually as the solutions are diluted (Figure 5c and 5c insert). This
way it appears that the potential of these nanoparticles to attract hydrophobic
agents can be tuned readily by dilution. In the results of complexation it was
seen that the hydrophobic content was a driving force for secondary
aggregation. In Figure 5b it is shown that the decrease in hydrophobic content
is accompanied by a decrease in scattered intensity i.e. a partial dissociation of
the aggregates. Both quantities change mildly at low dilutions and abruptly at
high dilutions (Figure 5b and c). It is notable that the hydrodynamic radius of
the complexes is non-monotonic. Initially the dissociation and drop in
hydrophobicity possibly releases some conformational degrees of freedom
resulting to an increase in size. Eventually the size drops due to break-up in
smaller aggregates [15].
Figure 5. (Continued)