Clogging and jamming of colloidal monolayers driven across a disordered landscape

Pietro Tierno
University of Barcelona, Spain

Abstract:
In this talk I will illustrate recent experimental results focused on investigating the clogging and jamming of interacting paramagnetic colloids driven through a quenched disordered landscape of fixed obstacles. Our system is inspired by recent theoretical results [1,2], and the magnetic particles are transported at a tunable speed via a travelling wave ratchet obtained with mobile magnetic domain walls [3]. When the particles are forced to cross a single aperture between two obstacles, we find an intermittent dynamics characterized by an exponential distribution of burst size. At the collective level, we observe that quenched disorder decreases the particle flow, but it also greatly enhances the 'faster is slower' effect, that occurs when increasing the particle speed [4]. Further, we show that clogging events may be controlled by tuning the pair interactions between the particles during transport, such that the colloidal flow decreases for repulsive interactions, but increases for anisotropic attraction [5]. We provide an experimental test-bed to investigate the crucial role of disorder on clogging and jamming in driven microscale matter.