Structured Fluids from Reduced Symmetry Molecules

Kent State University, Kent OH

Investigators

Abstract

TECHNICAL SUMMARY Recent studies of a team by A. Jákli, J.T. Gleeson and S. Sprunt at Kent State University have clearly demonstrated that fluids built from "bent-core" (or "banana" -shaped) molecules exhibit strikingly different properties from those composed of rod-shape materials; examples include anomalous flow viscosity and giant electro-mechanical coupling the latter being of high technological promise for molecular-scale energy conversion applications. These materials also apparently possess complex structure on the nanometer scale, and exhibit indications of novel states of matter. To develop a complete comprehension of these structures, the Kent State Group will utilize a powerful range of carefully targeted experimental techniques, available in house or through active participation in national user facilities. Specific new classes of reduced-symmetry materials to be investigated include molecules having W, T, X and H-shape, exciting new polymeric fluids and gels based on bent-core molecules, as well as previously uninvestigated low molecular weight bent-core molecules. The specific research objectives and scientific benefits of the proposed research are: (1) specific elucidation of nanoscopic structure in bent-core fluids; (2) investigation into the origins and limits of anomalously large coupling between electric properties and mechanical deformation (3) studies of strongly asymmetric bent-core molecules that form novel three-dimensional structures; (4) investigation of the optical and electro-mechanical properties of main- and side- chain polymers containing bent-core sub-units; and (5) studies of structured fluids under high magnetic fields to search for field-induced symmetry breaking transitions. NON-TECHNICAL SUMMARY Structured fluids are not only of fundamental scientific interest but have also enormous technological importance. Perhaps the most familiar example is liquid crystals, whose applications range from iPod screens to bullet-proof vests. The key factor determining the physical behavior of structured fluids is the symmetry properties of the molecular constituents. The team of A. Jákli, J.T. Gleeson and S. Sprunt at Kent State University will study compounds whose building blocks are not simple rods as in traditional liquid crystals, but either bent-shape, W, T, X and H shaped. A symmetry change in underlying molecule shape can lead to dramatically different and technologically promising behavior of a fluid composed of such molecules. This project offers the promise of significant advances in technology, such as low-cost, wearable (or potentially bio-implantable) electricity generators based on enhanced electro-mechanical coupling and a new generation of fast, low-power reflective color displays. The proposed research will provide critical feedback for synthetic chemists to improve material properties; key collaborators in this effort include Profs. R. Twieg (Department of Chemistry, Kent State University) and R. Verduzco (Department of Chemical Engineering, Rice University). The team's multi-faceted education program will train doctoral students to be effective players in a twenty-first century entrepreneurial environment. The principal investigators also will bring undergraduates, particularly from colleges serving traditionally under-represented groups, into a cutting-edge research environment, with the goal of increasing their participation in the high-tech workforce of tomorrow. Support from the Solid State and Materials Chemistry program is acknowledged.