Eur. Phys. J. E (2017) 40: 107
https://doi.org/10.1140/epje/i2017-11597-1

Regular Article

Resonant reshaping of colloidal clusters on a current carrying wire

¹ Université de Lorraine, LCP-A2MC, Institut de Chimie, Physique et Matériaux, 1 Bd. Arago, 57070, Metz, France
² CNRS, Institute Charles Sadron, 23 rue du Loess, BP 84047, 67034, Strasbourg, France
³ Institute for Theoretical Physics, Goethe-University, D-60438, Frankfurt am Main, Germany
⁴ Institute of Physics, Belgrade, Serbia

^* e-mail: kulic@unistra.fr

Received: 24 July 2017
Accepted: 16 November 2017
Published online: 1 December 2017

Abstract

Colloids in confined geometries promise a path towards tailored microscopic superstructures. Yet, a major roadblock is posed by kinetically trapped states that prevent the assemblies from reaching their anticipated shapes. We investigate magnetic colloids trapped on a cylindrical surface of a current carrying wire. If kinetic traps could be avoided the wire’s surface would act as an ideal mold for colloidal rings and helical fibers. We devise here a way to dynamically shake down the clusters and avoid kinetic traps in their energy landscape. A low frequency magnetic modulation wave around the wire axis effectively eliminates defects from the clusters and stretches them into slender rings and helical filaments. A theoretical model is developed that qualitatively explains the observed resonant reshaping response of clusters.