Liquid crystals are not only interesting for their role at the foundation of the 100-billion-dollar display industry. They are ideal materials to create soft structures that are controllable with external stimuli, and they provide a platform for physicists and chemists to address fundamental scientific questions. Unlike disordered molecules in common fluids, molecules in liquid crystals have some amount of order. Different types of liquid crystals have significant variability in terms of molecular structure and arrangement, which results in different mechanical and optical properties. Understanding the differences and the similarities between liquid crystal phases opens new paths to create not only the next generation of liquid crystal displays but also of a broader range of liquid crystal-based nanomaterials; furthermore, it helps answering fundamental questions regarding transitions between different states of matter. The goal of this research is to quantify the similarities and differences between liquid crystal phases by using polymers as mediators. Polymers can be dispersed in liquid crystals to create an “imprint†of the molecular order, which can then be transferred to a different liquid crystal. The goal is to devise a new classification method by measuring the compatibility of liquid crystal phases to accommodate distortions in the molecular ordering seen in other liquid crystal phases. The impact of this project extends beyond the physics community. Aligned networks of polymers are present in biological systems, and this project helps elucidate the role they have in tissues. Moreover, the broader goals of this project involve the creation of lightweight materials with customizable properties. In terms of societal impact, one goal is to involve young students and the general public through outreach events about liquid crystals, whose visual appeal makes them effective for illustrating science concepts. This project also aims to provide the basis for several undergraduate theses, including theses by under-represented minority students enrolled in a departmental bridge program in collaboration with Baltimore-area colleges.
This research project uses polymer networks templated in liquid crystals to impose deformation on other liquid crystal phases. Templated polymer networks can be obtained by dispersing monomers in low concentration in liquid crystals. Once cross-linked, the polymers carry the memory of the alignment. If the liquid crystal is removed from the polymer network, the same network can be re-filled with another material, which will have to comply with the deformations imposed by the polymers. The project has various goals, which include (a) the creation of templated polymer networks with specific distortions, (b) the analysis of the same networks re-filled with different kinds of liquid crystals, and (c) the quantitative measure of compatibility between the distortions and the identification of a “distance†between phases that provides a new classification method of liquid crystal phases. Other project goals involve using aligned polymer networks for 4D printing or as lightweight material for applications in biology or energy storage. Characterization of the liquid crystals are performed with optical microscopy, combined with electron microscopy and small angle x-ray scattering.
This Division of Materials Research (DMR) grant supports research to study phase structure and ordering in liquid crystals with funding from the Condensed Matter Physics (CMP) Program in DMR of the Mathematical and Physical Sciences (MPS) 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.
