Paper Number
SC13 

Session
Suspensions & Colloids

Title
Diffusion and equilibrium structure of polydisperse colloidal suspensions confined by a spherical cavity

Presentation Date and Time
October 15, 2018 (Monday) 5:00

Track / Room
Track 1 / Galleria I

Authors (Click on name to view author profile)

  1. Gonzalez, Emma (Stanford University, Chemical Engineering)
  2. Aponte-Rivera, Christian (Duke University, Mechanical Engineering and Material Science)
  3. Zia, Roseanna N. (Stanford University, Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Emma Gonzalez1, Christian Aponte-Rivera2, and Roseanna N. Zia1
1Chemical Engineering, Stanford University, Stanford, CA 94305-4125; 2Mechanical Engineering and Material Science, Duke University, Durham, NC 27705

Speaker / Presenter 
Gonzalez, Emma

Text of Abstract

Recent simulations of monodisperse colloidal suspensions confined by a spherical cavity demonstrate that both confinement and crowding produce qualitative changes in short and longtime transport rate processes and equilibrium material properties, arising from structural and dynamical heterogeneity associated with the confining cavity[1,2,3]. The theoretical and computational framework developed in these studies set the foundation for studying the dynamics of 3D microconfined suspensions. However, particle polydispersity in size, shape, and softness play a role in many biophysical confined systems such as the interior of eukaryotic cells[4], but such effects in 3D confinement have received little attention in the literature. In the present work, we extend our spherically-confined Stokesian dynamics model to account for size polydispersity, which is known to exert pronounced effects on structure and rheology in unbound suspensions, including reduced viscosity, changes in phase behavior, and flow-induced size segregation. We present the hydrodynamic coupling functions and computational model for a polydisperse suspension of colloids coupled by many body hydrodynamic and lubrication interactions to one another and to the confining cavity. We utilize our model to study the combined effects of hydrodynamic interactions, Brownian motion, crowding and particle polydispersity on the equilibrium structure, as well as on the short- and long-time equilibrium transport properties of spherically confined polydisperse colloidal suspensions. These four effects exert a qualitative influence on particle diffusion and structure, which are discussed in detail.

[1] Aponte-Rivera and Zia, Phys. Rev. Fluids, 2016. [2] Aponte-Rivera, Su, and Zia, J. Fluid Mech, 2018. [3] Aponte-Rivera, and Zia. Accurate 2-point microrheology inside a spherical cavity. In preparation. [4] Verkman, Trends Biochem Sci, Jan 2002.