Coarse-grained Molecular Dynamics Study on Block Copolymer Micelle/Nanoparticle Solutions Under Shear
Bryan Rolfe (Cornell University), Jaehun Chun (Pacific Northwest National Laboratory), Yong Joo (Cornell University)
Complex Fluids: Suspensions, Emulsions, and Gels
Wed 9:00 - 10:30
Barus-Holley 160
Recent experiments on dynamics of block polymer/nanoparticle solutions have shown that nanoparticles occupying interstitial sites within a micelle crystal affect a low-shear, long-range order and that the shear type and rate are important to the crystal structure. However, the connection between macroscopic variables and the resulting micelle/nanoparticle structure is not well understood. To elucidate the important role of micelle-nanoparticle dynamics in obtaining ordered nanoparticle structures, we present results of a coarse-grained molecular dynamics (CGMD) simulation with an explicit solvent that preserves hydrodynamic effects. Self-assembly of amphiphilic block copolymers into spherical and elongated micelles occurs within the framework of our simulations by appropriate tuning of the interaction parameters. As with experiments, type (simple or oscillatory) and strength of the applied shear are shown to be important in affecting both micelle morphology and the large-scale structure formed. Nanoparticle positioning within these micelle structures is further shown to be influenced by the micelle-nanoparticle dynamics dictated by the length of the micelle corona. The rheology and spatial order in our simulations is quantified for comparison to experimental work in the literature. Finally, we present three-dimensional structures of micelles after cessation of shear flow and the effect of nanoparticles on those 3D structures.