UNS: Liquid crystal templated three-dimensional nanoparticle assemblies

University Of California - Merced, Merced CA

Investigators

Abstract

CBET - 1507551 PI: Hirst, Linda The goal of this project is to design and characterize new microcapsules that have multifunctional capabilities. The fabrication of the microcapsules is based on the self-assembly of nanoparticles that uses liquid crystals to direct the assembly. Liquid crystals are ordered fluids that are best known for their use in computer displays. The nanoparticles are modified so that they form nanoparticle-rich liquid crystal droplets. These droplets act as a template for the self-assembly of nanoparticles into spherical shells, which can then be used in a variety of applications, including fluid photonic devices and molecular encapsulation and release. The investigators will use the project to develop new physics laboratory modules to introduce undergraduates to nanoscience, and the research team will expand its outreach to the public by organizing community college level workshops in nanotechnology. This project will design custom nanoparticle (NP) 3D assemblies using a liquid crystal (LC) based self-assembly method. A new technique will be explored to form thin shells of closely packed quantum dots ranging in diameter from 200 nanometers to 5 microns with walls that vary in thickness from 20 to 100 nanometers. The fabrication process is controlled by a liquid crystal phase transition. A nematic liquid crystal acts as the host phase into which mesogen-functionalized NPs (semiconducting, metallic and magnetic particles) are dispersed. The particles are surface-modified to incorporate a mesogenic (LC-like) ligand. Mesogen-functionalized NPs are an emerging class of materials that can assemble in LC/NP hybrid phases. Once formed, the capsules can be extracted from the host nematic phase and re-dispersed in different solvents for a variety of applications. The project goals are to design different NPs with mesogenic ligands using semiconducting, metallic and magnetic nanoparticles for 3D assembly in a host liquid crystal phase, fully elucidating the controlling parameters in the assembly process, and developing this new assembly method to create and test unique photonic structures and active multifunctional capsules.