The aim of this work is to create and study a new class of responsive materials called endoskeletal droplets. These are oil-in-water emulsion droplets that contain an internal scaffold of a soft network of crystalline solids. This endoskeleton provides the ability to mold and sustain a non-spherical shape. The balance of forces in these metastable structures can be used to trigger reorganization in shape in response to external stimuli, including changes to the droplet surface tension or weakening of the internal scaffold by increasing temperature. This project will study the structure, micromechanics, and responsiveness to stimuli of endoskeletal droplets. In addition, the fluid-fluid interfaces of these droplets will also be used to host or reject particles, which will further allow information flow through the droplet interface akin to the function of receptors in living cells.
Engineering shape anisotropy and shape change by colloids and particulates has applications in self-assembly, rheology, and drug delivery. Anisotropic shape leads to better deposition through enhanced collision cross-section, while the ability of structured droplets to adapt shape to curved surfaces will promote retention against hydrodynamic stresses. Prior work on shape changing particles has focused almost exclusively on solid materials. Preliminary studies of endoskeletal droplets highlight the rich possibilities for designing new responsive materials out of fluids and other simple materials that are of tremendous interest to technological applications as varied as commercial drug formulations, shampoos, detergents, cosmetics, and agricultural protectants. These broad impacts are enhanced by strong international and industrial partnerships. PhD students working at Delaware will have the opportunity to conduct research internships in the Complex Fluids Microstructures Group at P&G and at the University of New South Wales. In addition, the education and outreach activities of the PI will boost the interest of K-12 students and teachers in research and applications of soft materials and colloids.
The work is jointly funded by the Particulate and Multiphase Processes Program in Chemical, Biological, Environmental, and transport Division, Biomaterials Program in the Division of Materials Research,and BioMaPS funds from both divisions.
