Colloids with both patchy interactions and shape anisotropy can assemble into equilibrium structures that are ordered and self-limited in dimensionality. Because of the control of both unit cell symmetry and dimensionality, these structures have potential applications in functional materials with reconfigurable conductivity and/or mechanics. For example, metallodielecric Janus ellipsoids self-assemble into a variety of reconfigurable structures at dilute concentration (<i>Nature Materials</i> <b>14</b> 117-124 (2015)). Here we examine the impact of particle concentration on the self-assembly of such Janus ellipsoidal particles under a range of interaction conditions. We interrogate the spatial and orientational order of the Janus ellipsoids by means of confocal laser-scanning microscopy (CLSM), and access colloidal densities that lead to near close packing.  At low electrolyte concentrations, we find significant translational and orientational order, which is quantified by means of image analysis. Adding electrolyte to the suspension leads to concentrated solutions of fibers that display quasi-nematic order. These assemblies are subjected to electric fields in order to evaluate their reconfigurability under highly populated conditions. Applied electric fields tend to melt domain boundaries, align fibers, and induce lateral interactions.

Self-assembly and reconfiguration of Janus ellipsoids at high concentrations

253rd National Meeting (2017)

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