(138c) The Hydrodynamics of the Colloidal Glass Transition | AIChE

(138c) The Hydrodynamics of the Colloidal Glass Transition


Wang, J., Cornell University
Peng, X., University of Connecticut
Li, X., Texas Tech University
McKenna, G., Texas Tech University
We study via large­scale Stokesian dynamics simulation the colloidal glass transition and subsequent structural relaxation, utilizing controlled jumps from the liquid state into the putative glass region. We execute such volume-­fraction jumps with a range of quench depths and quench rates, where particle size increases at constant system volume. Here we focus on the effects of particle softness as well as lubrication and many-body long-range hydrodynamic interactions on post-­jump particle dynamics, where we implement the protocols of the McKenna-­Kovacs signature experiments (intrinsic iso­volume-­fraction) to study the approach to a stationary state. The results are compared with light scattering and rheology experiments. The system takes a finite time to reach a metastable intransient state at the widely­ accepted colloidal glass transition point, volume fraction 58%, challenging prior assertions that particle dynamics vanish at the glass transition. The exploration of even deeper quenches (higher final volume fractions) up to the random close packing reveals interesting convolution between aging and lag-time dynamics. Detailed study of structural and rheological evolution after the jump are utilized to elucidate the mechanistic process of glassy arrest.