Northwestern Events Calendar


Complex Systems Seminar: Professor Kathleen J. Stebe: Embedded energy landscapes in soft matter to direct colloid motion

When: Thursday, March 21, 2019
2:00 PM - 3:30 PM Central

Where: Technological Institute, F160, 2145 Sheridan Road, Evanston, IL 60208 map it

Audience: Faculty/Staff - Student - Public - Post Docs/Docs - Graduate Students

Contact: Cristian Pennington   (847) 491-3645

Group: Physics and Astronomy Complex Systems Seminars

Category: Academic


The ability to dictate the trajectories and docking sites of colloidal objects has far-reaching implications in fields ranging from reconfigurable materials to intelligent systems. We have been developing embed energy landscapes that organize colloidal particles using confined nematic liquid crystals (NLCs) near undulating boundaries. Related concepts have been developed using defect structures within NLCs director fields. However, while these structures can organize colloids within them, they typically trap colloids, preventing reconfiguration. To avoid such trapping, we design director fields that, in the absence of the colloids, are defect-free, but feature gentle distortions that can be sensed by colloids placed within the domain. This NLC director field gently guides colloid motion. We develop these concepts by placing a boundary of alternating hills and wells with well-defined anchoring in contact with the NLC. This embeds an energy landscape that dictates anisotropic particle orientation, particle paths and defines multi-stable equilibria. These strategies to direct colloid motion can be combined with external fields to afford additional control over reconfigurable systems and in microrobotics applications.

Professor Kathleen J. Stebe, University of Pennsylvania

Host: Michelle Driscoll

Keywords: Physics, Astronomy, Complex Systems

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