Cargo transport by dissipative solitons-director bullets in nematics*

An alternating current (AC) electric field applied to a uniformly aligned nematic liquid crystal is capable to excite and drive particle-like three-dimensional dissipative solitons, the so-called director bullets [1, 2]. The bullets represent regions of a distorted molecular orientation of broken left-right or head-tail symmetry that propagate perpendicularly to the driving field. Here, we demonstrate that the bullets can be generated around colloidal spheres with both tangential and radial anchoring, dispersed in the nematic. The effect represents a soliton-mediated liquid crystal-enabled electrophoresis, in which the electric field first breaks the quadrupolar symmetry of the director field around the sphere and then drives oscillations of this asymmetric director field to power a directional motion of the sphere dressed in the soliton. The effect can be used to transport microscopic cargo when modes of liquid crystal-enabled elecrtokinetics based on static asymmetry are ineffective, which is the case of tangentially anchored inclusions.
[1] B.-X. Li, et al., Nat. Commun. 9, 2912 (2018).
[2] B.-X. Li,et al., Nat. Commun. 10, 3749 (2019).