NANOPARTICLES FROM COMPLEXATION OF CHITOSAN AND POLY(SODIUM METHACRYLATE): light scattering studies
Interpolyelectrolyte complexes, dynamics light scattering, small angle X-ray scattering, chitosan.
Interpolyelectrolyte complex (IPEC) dispersions were prepared from chitosan and poly(sodium acrylate), NaPMA, by mixing their solutions., at different carboxyl to aminium molar ratio, . Gyration radius was determined by SAXS and showed that, as increased, IPEC dimensions decreased and reached a minimum at , which was considered the ratio at which IPEC cluster dimensions was minimum, following collapse and growth of larger particles. Pair distance distributions, , became narrower up to , increasing its width from this point. Relaxation-related parameters from DLS intensity correlation functions (ICF) identified three main relaxation process. The fast process, related to free polyelectrolyte molecules random motion disappeared as was increased. The other two relaxation process were a function of and presented marked changes at . At the same value of the energy of activation for the average relaxation rate showed the occurrence of a clear change in the nature of IPEC-related interactions. As hydrodynamic diameter, determined by DLS was much larger than the gyration radius determined by SAXS, IPEC particles could be described as being composed by a core, rich in segregated, insoluble material, enveloped by IPEC soluble clusters, possibly in the form of water-rich gels.