Thermodynamics, Microstructure and Rheology of Polyelectrolyte-Surfactant Coacervation
Coacervation in mixture of polyelectrolytes (PEs) and surfactants with opposite charge is common in nature and is also technologically important for applied research such as food, cosmetics and pharmaceutics. Of particular interest is the delivery and controlled release of active compounds (i.e., functional oils, antibacterial agents) via coacervate-encapsulation during the usage of many consumer health care products. The successful design of an appropriate coacervation and delivery process best incorporates knowledge of the molecular interactions governing such self-assembling systems.
To better understand the molecular forces controlling the structure and phase behavior of coacervates, we have investigated a series of model mixtures of varying polymer charge density and surfactant alkyl chain hydrophobicity, holding constant as many as possible of the auxiliary properties. The goal is a quantitative link between molecular interactions, phase behavior, microstructure and coacervate rheological performance. To achieve this, we combined a wide range of experimental techniques for thermodynamic measurements with methods for microstructure characterizations, and rheology at different structural levels.