(64d) Dynamic Properties of Polyelectrolyte-Surfactant Complexes Regulate the Escape of Microdroplets Elastically Trapped in Thermotropic Liquid Crystals

The dynamic behaviors of polyelectrolytes and their complexes with surfactants formed at fluid interfaces play a key role in colloidal phenomena such as stabilization of emulsions and control of interfacial rheology. In this presentation, we describe how the dynamics of polyelectrolyte-surfactant complexes can be studied by using aqueous interfaces of thermotropic liquid crystals (LCs). In particular, we will show that the orientational responses of LCs can be used to quantify the lifetimes of polyelectrolyte-surfactant complexes formed at their interfaces and also to infer key aspects of the structure of the complexes. Additionally, experimental measurements will be presented that demonstrate how the dynamics of assembly and disassembly of polyelectrolyte-surfactant complexes at LC interfaces can regulate the escape of surfactant-stabilized aqueous microdroplets that are elastically trapped within the LC. The latter result provides a fresh approach for the design of emulsions that can be programmed to release their contents. Overall, the results in this presentation provide new insight into the dynamics of polyelectrolyte-surfactant complexes at aqueous-LC interfaces and their influence on LC ordering.