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Abstract

K. Peddireddy, S. Copar, K. V. Le, I. Musevic, C. Bahr and V. S. R. Jampani, PNAS, 118(14) e2011174118, 2021 It is still a challenge to reproduce the shape diversity and controlled re-configurability of closed surfaces and filamentous structures, which are generally found in cellular colonies and living tissues. In this work, liquid crystal (LC) droplets are self-shaped into anisotropic and three-dimensional superstructures, including LC fibres, LC helices, and differently shaped LC vesicles by mixing two surfactants with an LC dispersed phase and an aqueous continuous phase. The authors tune the bulk LC elasticity and interfacial energy through thermal stimuli, thus transforming an emulsion of polydispersed, spherical nematic droplets into a number of uniform-diameter fibres with multiple branches. Furthermore, when the nematic LC is cooled to the smectic-A phase, the nematic fibres are broken into monodispersed microdroplets with a tunable diameter dictated by the cooling rate. The experimental findings are further supported by a theoretical model of equilibrium interface shapes. The shape transformation is induced by negative interfacial energy, which promotes a spontaneous increase of the interfacial area at a fixed LC volume. This method is successfully applied to many different LC materials and phases, demonstrating a universal mechanism for shape transformation in complex fluids.