Polyelectrolytes: Theory, Properties and Applications

Complexes of Poly[Sodium(Sulfamate/Carboxylate)Isoprene] ... 93

Figure 1. Scattered intensity (at 90°) from mixed solutions of fixed SCPI concentration
(5.128x10-^4 g/ml) as a function of DTMAB concentration.

In combination with the invariant scattered intensity in this regime (Figure

1. we can conclude that the surfactant molecules attach on the SCPI chains
   without causing significant change in molecular weight nevertheless having a
   strong conformational impact [13, 14].
   The electrostatic binding neutralizes part of the SCPI chains charge and at
   the same time imports new hydrophobic units that increase the hydrophobic
   content of the chains. Both effects result in shrinkage of the aggregates. In the
   second complexation regime (푐퐷푇푀퐴퐵>4x 10 −^4 g/ml) the aggregate size
   increases (accompanied by the increase in scattered intensity). Here the
   electrostatic repulsions between the aggregates are reduced and additionally
   their increased hydrophobic content enhances the inter-aggregate bridging and
   clustering. Similarly we have observed initial shrinkage in the kinetics of
   triblock doubly-responsive polyelectrolyte aggregates upon binding of
   oppositely charged globular proteins [15]. The polydispersity of the clustered
   aggregates is significantly reduced (Figure 2, inset) in comparison to the initial
   aggregates highlighting the formation of well-defined colloidal nanoparticles.