(477e) Magnetic Control over Dynamic Clustering of Colloids | AIChE

(477e) Magnetic Control over Dynamic Clustering of Colloids


Bharti, B. - Presenter, Louisiana State University
Al Harraq, A., Louisiana State University
Understanding the arrangement of individual building blocks in response to changes in the free energy available is a challenge of non-equilibrium matter. The push-and-pull balance between ordered and disordered states has been described by a ratio of attraction and repulsion, yet no experimental demonstration with a dynamic energy landscape is available. Here, we uncover the ‘dual nature’ of ferrofluids, particulate and continuous, to design a colloidal platform that couples competitive interactions with non-equilibrium dynamics. Using a binary suspension of microspheres in ferrofluid, we describe cyclical order-disorder-order transitions, and we access a dynamic cluster state. We show that crystal and fluid states represent two extremes in the competition between attraction and repulsion, while arrangement into clusters is a pseudo-equilibrium only observed from the true balance of interaction forces.