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Abstract

B. Senyuk, A. Mozaffari, K. Crust, R. Zhang, J. J. de Pablo, and I. I. Smalyukh, Science Advances, 7, eabg0377, 2021. From foods and drinks to health and personal care products, emulsions are common but import to our daily life. Nematic emulsions composed of nematic liquid crystals and other liquids have attracted great attention due to their potential applications in many areas ranging from bio-detection to smart windows, which mainly rely on changes of molecular alignment structures around the drops in response to chemical, thermal, electric, and other stimuli. In this work, the authors show that absorption or desorption of trace amounts of common surfactants can drive continuous transformations of elastic multipoles induced by the droplets within the uniformly aligned nematic host. Out-of-equilibrium dynamics of director structures emerge from a controlled selfassembly or desorption of different surfactants at the drop-nematic interfaces, with ensuing forward and reverse transformations between elastic dipoles, quadrupoles, octupoles, and hexadecapoles. The authors also characterise inter-transformations of droplet-induced surface and bulk defects, probe elastic pair interactions, and discuss emergent prospects for fundamental science and applications of the reconfigurable nematic emulsions.