The effects of salt on coacervate formed by polyDADMAC and gum arabic

Abstract

Complex coacervation is a liquid-liquid phase separation phenomenon that occurred in a solution between oppositely charged macromolecular species through electrostatic interaction. The first reported study of complex coacervation was observed almost a century ago, usually produced from proteins and polysaccharides that results in a coexistence of a dense liquid phase (coacervate phase) and a dilute liquid phase (aqueous phase). Coacervate functionality has been used in a variety of common applications in the personal care, pharmaceutical, food industries, and there has been a growing interest in industrial materials design and self-assembled material production. The formation of stable complex coacervates is strongly dependent upon parameters such as pH of solution, ionic strength, mixing ratio, temperature, polymer molecular weight, total polymer concentration and polyelectrolyte charge ratio. The goal of this research is to better understand the impacts of specific parameters such ionic strength, pH, and mixing ratio on the environment conditions, with the goal of optimizing the formation of polymer-polymer complex coacervation between polyDADMAC and gum arabic. The influence of different salt types and salt concentrations on the coacervate process was investigated and characterized using turbidity. The effect can be described by the Hofmeister series, which revealed the importance of ion-specific interactions for material designed coacervate used in complex environments. Monovalent salts and divalent salts with respect to different anions and cations types were used on the extent of coacervate formation. This allows for more theoretically precise and systematic research into the impact of salt on the formation of coacervate.