Aggregation behavior of pluronic F127 solutions in presence of chitosan/clay nanocomposites examined by dynamic light scattering

Abstract

HypothesisAlthough several researches have explored the dynamics of pluronic aqueous solutions under different conditions, little is known about the dynamical properties of pluronic copolymers in presence of nanoparticles. Knowing and understanding the fundamental dynamical behavior of such systems is crucial to optimize the formulation of high performance multifunctional structures. ExperimentsIn the present work, dynamic light scattering (DLS) is used to investigate the temperature dependence of the dynamical properties of Pluronic F127 aqueous solutions in presence of intercalated chitosan/clay nanocomposites; for comparison, the pluronic aqueous solution and the binary systems pluronic/chitosan and pluronic/montmorillonite having the same copolymer concentration were also investigated. FindingsDLS results show that the pluronic solution is characterized by a fast and a slow diffusion process. The faster diffusion is associated with the unimers interchange between micelles whereas the slower one is ascribed to the presence of micellar clusters that undergo dehydration as the temperature increases. Starting from these observations, the dynamics of the pluronic-based/water systems was analyzed and, depending upon solution temperature, the observed decays were attributed to differently sized entities. The DLS findings give strong evidence for the coexistence of complex states of aggregation allowing us to get a better insight into the architecture of the investigated systems.