CAREER: Electrically- and Optically-Controlled Self-Assembly in Liquid Crystals

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

Proposal 0847782, CAREER: Electrically- & optically-controlled self-assembly in liquid crystals Ivan I. Smalyukh, Asst. Professor of Physics, Univ. of Colorado at Boulder TECHNICAL SUMMARY: The PI will conduct interdisciplinary research at the interfaces of liquid crystal (LC) physics, nanoscience, and photonics, focusing on fundamental and applied aspects of self-assembly in LC composite materials. He seeks to identify the organizing principles behind self-organization of nano- and micro-sized particles dispersed in LC mesophases ranging from the classical thermotropic nematic to the novel phases composed of bent-core molecules, and to those formed by DNA and live bacteria. PI will establish how director structures around nano- and micro-sized particles immersed in LCs depend on particle?s shape, size, surface treatment, type of the LC mesophase, and applied external fields. He will use topological defects, nano-scale periodic defect arrays in LC blue phases, and strongly-distorted director structures for spatial patterning of particles. LC?s sensitivity to external fields, surface treatment, temperature, and light will enable unprecedented degrees of control over formed self-assembled structures of molecules and inclusions of various shapes and chemical composition. In order to engage this class of problems, the PI will utilize fluorescence-detectable nano- and micro-sized particles ranging from nanocrystals to live bacteria, so that their spatial localization and alignment in the LC samples can be revealed using fluorescence confocal imaging. To get insights into the physics phenomena behind the self-assembly, optical imaging and laser manipulation will be combined synergistically with freeze fracture transmission electron microscopy and synchrotron x-ray micro-beam diffraction, so that the hierarchical self-assembly structures from nanometer to tens of microns length scales can be known. The fundamental phenomena will be examined in the broader contexts ranging from development of self-assembly-based tunable optical metamaterials to understanding bacteria-extracellular matrix interactions in biofilms. This work will advance knowledge of self-assembly in complex fluids and will impinge on fields as diverse as nano-scale interactions and ensuing collective behavior, novel display technologies, efficient conversion of solar energy to electricity using inexpensive organic solar cells, metamaterial fabrication, and bacterial biofilms. PI is will integrate the proposed research projects into a broad range of education and outreach activities. NON-TECHNICAL SUMMARY: PI is researching organizing principles of nanoparticle and molecular self-assembly into precisely controlled structures in liquid crystals. Fundamental understanding of this ?smart? assembly will shed light on biological organization at the cellular and molecular levels and will enable development of new electrically- and optically-controlled materials with unique properties needed for wide-angle beam steering, efficient conversion of solar energy into electricity, and for practical devices of importance to society, such as flexible displays and data storage devices. PI will integrate this research into educational and outreach programs, including ?Light, Color, & Matter? Wizard Shows in elementary and secondary schools, Science Tours for high school students, advising student chapters of professional societies, providing research experiences for students and faculty from minority-serving institutions and helping them to define their educational and research goals, teaching ?Liquid Crystals: From Fundamentals to Applications? conference short courses for liquid crystal industry, participating in the SPIE visiting lecturer program by giving public lectures worldwide, and organizing international conferences and inter-continental advanced materials and photonics (I-CAMP) summer schools. Lectures of the I-CAMP summer schools will be webcast in real time and then transformed into web-based video archives and interactive tutorials. Moreover, these summer schools will be integrated with outreach forums and career development programs for students and postdoctoral fellows and will attract underrepresented minority participants.