Tunable Colloidal Spinners: A Novel System for Chiral Active Soft Matter
Pavel A. Libet1, Egor V. Yakovlev1, Nikita P. Kryuchkov1, Ivan V. Simkin1, Andrei V. Sapelkin2, Stanislav O. Yurchenko1;
1 Centre for Soft Matter and Physics of Fluids, Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, 105005 Moscow, Russia
2 Department of Physics and Astronomy, Queen Mary University of London, London E1 4NS, England
Abstract
The rotational dynamics of microparticles in liquids have a wide range of applications, including chemical microreactors, biotechnologies, microfluidic devices, tunable heat and mass transfer, and fundamental understanding of chiral active soft matter. Here, we report on the study of two effects in colloids in rotating electric fields: (i) the rotation of individual colloidal particles in rotating electric field and (ii) precession of pairs of particles. We show that the mechanism responsible for the rotation of individual particles is related to the time lag between the external field applied to the particle and the particle polarization. Using numerical simulations and experiments with silica particles in a water-based solvent, we prove that the observed rotation of particle pairs and triplets is governed by the tunable rotation of individual particles and can be explained and described by the action of hydrodynamic forces.
Our findings demonstrate that colloidal suspensions in rotating electric fields, under some conditions, represent a novel class of chiral soft active matter—tunable colloidal spinners. We find that the angular velocity of a pair of colloidal spinners is inversely proportional to their interparticle distance. This tunable control over rotation opens up new avenues for manipulating the dynamics of colloidal systems, with potential applications in microfluidic devices, self-assembly, and biotechnologies.
The experimental study and data post-processing were supported by the Russian Science Foundation (Grant No. 22-72-10128). Calculations of electrostatic and hydrodynamic interactions, as well as the analysis of active spinner dynamics, were supported by the Russian Science Foundation (Grant No. 20-72-10161).
Speaker
Pavel A. Libet
Bauman Moscow State Technical University, Moscow, Russia
Russia
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