UNS: Synthesis and Dynamics of Elastic Capsules with Controlled Interfacial Elasticity

Carnegie Mellon University, Pittsburgh PA

Investigators

Abstract

CBET - 1511016 PI: Shelley L. Anna Capsules are liquid drops or bubbles that have molecules or nanoparticles adsorbed onto their outer surfaces, which gives them unique mechanical properties. Capsules are used in a variety of products including drug delivery formulations, cosmetics, paints, inks, and foodstuffs. This project will investigate how the distribution of nanoparticles on the surface of a capsule affects the elasticity of the capsule interface and the deformation of the capsule as a whole under precisely controlled conditions. The results of the study will provide scientists and engineers with information that will help them optimize capsule formulations for use in a wide array of specialized products. Results from the project will also be used to develop educational modules to engage K-12 students and course content for university undergraduate and graduate students. A microfluidic device will be used to adsorb a cationic surfactant-nanoparticle complex onto the interface of a gaseous bubble as it translates along a microchannel. The goal of the experiment is to show how the properties of the capsule interface, especially its elasticity, are affected by the concentration of adsorbed nanoparticle complexes and their spatial distribution along the bubble surface, which will be determined using methods such as electron microscopy. Dynamical properties of the capsule interfaces will be investigated using a microtensiometer developed at Carnegie Mellon University. The microtensiometer will be used to measure interfacial tension and interfacial elasticity of the capsule and correlate it with interfacial coverage of the surfactant-nanoparticle complexes. Finally, scale-up of capsule production to obtain a sufficient number of capsules for rheological measurements of capsule suspensions will be investigated by using parallel microfluidic channels and complex microfluidic circuits. The results of the studies will be disseminated directly to industrial counterparts through workshops and short courses organized at Carnegie Mellon University.