RUI: Thermoreversible hydrogen bonding in mesophase formation: Enhancing stability and formation

University Of Wisconsin-Eau Claire, Eau Claire WI

Investigators

Abstract

Non-technical Summary: Liquid Crystals have become a mainstay of the scientific and technological community, emerging as one of the leading display materials of the past decade. An increased understanding of the stability of a liquid crystalline materials could would have considerable impact on the optical display industry. This project will prepare liquid crystalline systems that combine the stabilities of covalent species with the healing capabilities of hydrogen bonded chain structures, and through the incorporation of these groups, the PI plans to introduce important new and beneficial characteristics while at the same time improving the stability of liquid crystalline materials. Beyond the scientific impact of this project, the project will enhance the research infrastructure and support human resource development at the University of Wisconsin- Eau Claire. This low-cost public institution has a long-established tradition of strong undergraduate/faculty research collaboration that rivals those of top liberal arts colleges. As a result, a large fraction of UWEC undergraduates matriculate to graduate programs. Almost half of the student body are low-income, first generation students, and about 60% are female, both of which are underrepresented in the scientific communities. The research activities described will greatly enhance student training and intellectual development through hands-on experience with sophisticated equipment and the opportunity to present their findings at national meetings. Technical Summary: With support from the Solid State and Materials Chemistry program in the Division of Materials Research, this project will study the creation of new liquid crystalline systems. Liquid crystalline networks are an area that has received considerable attention due to the ability of the materials to couple the order of the mesogenic directors to the elasticity and deformation of the materials. The application of thermoreversible assemblies to liquid crystalline networks is a relatively unexamined area. The assembly of liquid crystalline materials using non-covalent interactions offers many interesting features involving living polymeric systems and the ability of the liquid crystals to self-heal and repair macroscale structural defects. This work will have a broad impact on the field of supramolecular liquid crystals. The creation of these new LC assemblies will provide valuable insight into the ability of a mesophase to stabilize in unfavorable, constrained (networked) conditions, as well as an understanding of stoichiometric balance and highly flexible non-mesogenic competitive assemblies. The same associations will be used to form both the networks and the mesogens. This association will vary according to functionality of the networking agent, rigidity of the hydrogen bond accepting group and flexibility of the networking agents. Additionally, the competition of different mesogens arising from identical starting mixtures will be investigated. Results from this project will provide insight into the nature of the formation of a mesophase, and a comparison of the quantity and strength of supramolecular forces involved in the formation of liquid crystals. In particular, the behavior of mesophase formation and stabilization in crosslinked conditions, and the role and interplay between rigidity and flexibility of the hydrogen bond acceptors plays for mesogen formation and mesophase stability.