Inclusions in Soft Matter: Opportunities for Directed Assembly

Kathleen Stebe


Thursday, June 4, 2015 - 4:00pm


1519 Engineering II


Kathleen Stebe - U Penn

Colloidal particles are often directed to assemble by applying external fields to steer them into well‐defined structures at given locations. We are developing alternative strategies based on fields that arise when a colloid is placed within soft matter to form an inclusion that generates a potential field. For example, a particle adsorbed on a fluid interface can distort that interface to satisfy its wetting boundary conditions. The distortion has an associated energy field given by the product of its interfacial area and the surface tension. Fields generated by neighboring particles interact to drive assembly; preferred orientations for anisotropic objects emerge. Interface curvature couples to the particle’s capillary energy. By molding the curvature, we can define fields that drive particles along pre‐determined paths to well defined locations with deterministic energies. This example captures the emergent nature of the interactions, and their potential importance in schemes to make reconfigurable materials, since interfaces and their associated capillary energy landscapes can be readily reconfigured.

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