Paper Number
PO28
Session
Poster Session
Title
Tracer transport probes relaxation and structure of attractive and repulsive glassy liquids
Presentation Date and Time
October 17, 2018 (Wednesday) 6:30
Track / Room
Poster Session / Woodway II/III
Authors
- Roberts, Ryan C. (University of Houston, Chemical Engineering)
- Poling-Skutvik, Ryan (University of Houston, Chemical and Biomolecular Engineering)
- Palmer, Jeremy C. (University of Houston, Chemical and Biomolecular Engineering)
- Conrad, Jacinta C. (University of Houston, Chemical and Biomolecular Engineering)
Author and Affiliation Lines
Ryan C. Roberts, Ryan Poling-Skutvik, Jeremy C. Palmer, and Jacinta C. Conrad
Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204
Speaker / Presenter
Roberts, Ryan C.
Text of Abstract
Dynamic coupling of small penetrants to slow, cooperative relaxations within crowded cells, supercooled liquids, and polymer matrices has broad consequences for applications ranging from drug delivery to nanocomposite processing. Similarly, understanding the dynamics of dopants is crucial for interpreting experiments that probe viscosity during vitrification. Interactions between the constituents of these and other disordered media alter the cooperative relaxations, but their effect on penetrant dynamics remains incompletely understood. We use molecular dynamics simulations to show that the motions of hard-sphere tracer particles probe differences in local structure and cooperative relaxation processes in attractive and repulsive glassy liquid matrices with equal bulk packing fractions and long-time diffusivities. Coupling of the tracer dynamics to collective relaxations in each matrix affects the shape of tracer trajectories, which are fractal within the repulsive matrix and more compact in the attractive. These results reveal that the structure of relaxations controls penetrant transport and dispersion in cooperatively relaxing systems and provide insight into dynamical heterogeneity within glassy liquids.