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Juan de Pablo (University of Chicago)

Date: Thu. April 20th, 2017, 4:00 pm-5:00 pm
Location: Rockefeller 301

Nanoparticles in liquid crystals, and liquid crystals in nanoparticles.
 
Liquid crystals are remarkably sensitive to interfacial interactions. Small perturbations at a liquid crystal interface can in fact be amplified over relative long distances, thereby providing the basis for a wide range of applications. Our recent research efforts have focused on the reverse phenomenon; that is, we have sought to manipulate the interfacial assembly of nanoparticles or the organization of surface active molecules by controlling the structure of a liquid crystal. This presentation will consist of a review of the basic principles that are responsible for liquid crystal-mediated interactions, followed by demonstrations of those principles in the context of two types of systems. In the first, a liquid crystal is used to direct the assembly of nanoparticles. Through a combination of molecular and continuum models, we explain how minute changes in interfacial energy and particle size can lead to liquid-crystal induced interactions that can span multiple orders of magnitude. In the second application, the structure of a liquid crystal is controlled by confinement. We explain how confinement in micro-droplets causes the morphology of liquid crystals to depend on a delicate balance between bulk and interfacial contributions to the free energy; that balance can be easily perturbed by adsorption of analytes at the interface, thereby providing the basis for development of inexpensive, ultrasensitive devices for chemical or biological sensing.
Page last modified: April 14, 2017