Stringlike correlated motion in the dynamics of supercooled polymer melts

Polymer-specific effects of bulk relaxation and stringlike correlated motion in the dynamics of supercooled polymer melt

Modifying fragility and collective motion in polymer melts with nanoparticles.

We investigate the impact of nanoparticles (NP) on the fragility and cooperative stringlike motion in a model glass-forming polymer melt by molecular dynamics simulation. The NP cause significant changes to both the fragility and the average length of stringlike motion, where the effect depends on the NP-polymer interaction and NP concentration. We interpret these changes via the Adam-Gibbs (AG...

Effect of chain stiffness and temperature on the dynamics and microstructure of crystallizable bead-spring polymer melts.

We contrast the dynamics in model unentangled polymer melts of chains of three different stiffnesses: flexible, intermediate, and rodlike. Flexible and rodlike chains, which readily solidify into close-packed crystals (respectively, with randomly oriented and nematically aligned chains), display simple melt dynamics with Arrhenius temperature dependence and a discontinuous change upon solidific...

Polymer-specific effects of bulk relaxation and stringlike correlated motion in the dynamics of a supercooled polymer melt

We analyze dynamical heterogeneities in a simulated ‘‘bead-spring’’ model of a nonentangled, supercooled polymer melt. We explore the importance of chain connectivity on the spatially heterogeneous motion of the monomers. We find that when monomers move, they tend to follow each other in one-dimensional paths, forming strings as previously reported in atomic liquids and colloidal suspensions. T...

String-like Correlated Motion in Supercooled Liquids and Polymers

Title of dissertation: SPATIALLY HETEROGENEOUS DYNAMICS AND STRING-LIKE CORRELATED MOTION IN SUPERCOOLED LIQUIDS AND POLYMERS Yeshitila Gebremichael, Doctor of Philosophy, 2004 Dissertation directed by: Professor Sharon C. Glotzer Chemical Engineering Department University of Michigan, Ann Arbor, MI Professor John D. Weeks Chemical Physics Program University of Maryland, College Park, MD Dense ...