(640a) Classical Colloids Meet Nanoscience: New Classes Of Particulate Stabilizers For Foams, Emulsions And Microcapsules

One of the major objectives of the research in colloidal and nanoscale engineering is the development of controllable, scalable, rapid and cost-effective processes for the synthesis of functional particles and particle assemblies. This talk will present examples of synthesis of new particles and structures that can dramatically enhance the properties of ?classical? colloidal systems such as foams and emulsions. First, we developed a novel process for fabrication of polymer microrods based on liquid-liquid emulsification under shear stress. The process allows control of the microrod size and aspect ratio and is easily scalable so these microrods can become as ubiquitous as latex spheres. Hydrophobic microrod suspensions act as "superstabilizers" of foams and emulsions by forming rigid adsorption shells around the bubbles or droplets. The superstabilization effect is made possible by rod entanglement, formation of "hairy" shells, and sustaining of thick water films. New types of capsules based on rod shells will also be demonstrated. Results from the ongoing research on the synthesis of superstabilizer particles from FDA-approved modified cellulose will be presented. These in-situ formed particles readily adsorb at water-air or water-oil interfaces created during foam and emulsion shearing/blending. Under optimal conditions, these foams and emulsions were stable for more than 60 days. Such hydrophobic cellulose particle stabilizers could replace conventional surfactants for food and other applications. We will also discuss a few new facile and scalable processes for the synthesis of responsive polymeric microcapsules in spontaneously formed double emulsions.