Chemistry Seminar Series: Stabilization of water-in-water emulsions and their use to create stable microcapsules

Biographical Information

Prof. Taco Nicolai is a CNRS research director working at the Institute of Molecules and Materials of Le Mans at Le Mans University in France. Dr Nicolai’s expertise includes the structure and dynamics of soft matter and more specifically that formed by aggregation and gelation of proteins and polysaccharides in aqueous solution as well as mixtures thereof. A more recent focus of his research is on the stabilization of water-in-water emulsions. He has published close to 300 peer reviewed papers. Dr. Nicolai graduated from Leiden University (Netherlands), where he also obtained his PhD degree.

Abstract

Water-in-water emulsions can be formed by mixing aqueous solutions of incompatible macromolecules. I will show that such emulsions can be stabilized by adding a small amount of a third component, a colloid or a polymer, that is compatible with both phases but nevertheless accumulates at the interface. However, accumulation at the interface does not guarantee stability, but depends on their interaction with each other. I will also discuss the interaction between different stabilized droplets in mixtures. Finally, I will discuss how one can use such emulsions to create stable microcapsules, by crosslinking the particles at the interface so that they form a solid shell. Different methods are presented to form microcapsules with different sizes and shell thickness.