In this talk I will present recent progress in modeling and simulating the collective hydrodynamics of (1) amphiphiles (such as lipid macromolecules) and (2) drops of active fluids. In (1) I will describe how hydrophobic interactions between amphiphiles in solvents dominate their collective hydrodynamics and dictate their self assembly into micelles, planar membranes, and vesicle membranes. Furthermore we show that such collectives behave with mechanical properties described by Helfrich free-energy of an elastic membrane. We also demonstrate that under flowing conditions the collective exhibits hydrodynamics observed for their macroscopic counter parts. In (2) I will first formulate the active fluids in terms of active nematic liquid, and I will demonstrate how a deformable interface couples to the activity in the interior fluid. I will then show the collective hydrodynamics of active drops driven by their interior activities.
(1) is a collaboration with Szu-Pei Fu and Rolf Ryham from Fordham University. (2) is a collaboration with David Stein and Mike Shelley from Flatiron Institute. This work is supported by NSF and Flatiron Institute.