Routes of Relaxation and Reconfiguration in Soft Matter

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

Nontechnical Abstract: This materials research will unravel new concepts about frustration and reconfiguration of disordered matter that could lead to better control of magnetic materials, to creation of tougher glasses and coatings, and to synthesis of responsive soft materials. Broadly, the experimental project develops new ability to formulate and manipulate micro- and nano-particles and macromolecules in solution. Moreover, the project develops new ways to observe these materials based on cutting-edge optical and computational techniques. The research thus strengthens the science that underlies industries involved with sensing/actuation, microfluidics, drug delivery, photonics, printing, coatings, cosmetics, and agriculture, and thereby positively impacts US technology infrastructure and economy. Finally, this activity will train a new generation of scientists and engineers in the areas of soft materials behavior and formulation, optical microscopy, electro-optics, microfluidics, rheology, and computation. The emerging PhD students and post-docs will enter the nation’s work force, and a diverse group of undergraduate and high school participants will be stimulated to pursue STEM education/career choices as a result of this research activity. Technical Abstract: This experimental project explores fundamental properties of complex fluids and soft materials. Reconfiguration, broadly defined, unifies the research. The research will develop and use sample systems based on colloidal particle suspensions, liquid crystals, and drops to explore the phenomenology of assembly, reconfiguration, response-to-frustration, and relaxation. Importantly, the soft systems offer unique experimental knobs that permit tuning of an energy scale, force parameter, or boundary condition to answer physics questions. The colloid research employs novel particle systems, state-of-the-art video microscopy, and frontier computational analysis tools probe structural relaxation and rearrangement in frustrated colloidal antiferromagnets, colloidal glasses, and colloidal supercooled liquids. The liquid crystal research is oriented towards drops containing liquid crystals. Reconfiguration research, in this case, will develop understanding about the remarkable shape-transitions of drops containing liquid crystal polymers and oligomers. Like the colloidal systems, these behaviors are driven by the delicate balance of interfacial energy, bulk elasticity, and geometry characteristic of soft matter, but they have a new twist: molecular chain polydispersity drives the morphological transformations. Knowledge gained should enable manipulation and crafting of novel routes to assemble complex fluids and will make intellectual connections to patterning effects in living matter that exploit molecular heterogeneity. This Division of Materials Research (DMR) grant supports research to explore fundamental properties of complex fluids and soft materials with funding from the Condensed Matter Physics (CMP) Program in DMR of the Mathematical and Physical Sciences Directorate. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.