Tracer Transport Probes Relaxation and Structure of Attractive and Repulsive Glassy Liquids
| Autor: | Ryan Poling-Skutvik, Ryan C. Roberts, Jeremy C. Palmer, Jacinta C. Conrad |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
Nanocomposite Materials science 02 engineering and technology Polymer 021001 nanoscience & nanotechnology 01 natural sciences Condensed Matter::Soft Condensed Matter Molecular dynamics Matrix (mathematics) Fractal Penetrant (mechanical electrical or structural) chemistry Chemical physics 0103 physical sciences General Materials Science Dynamical heterogeneity Physical and Theoretical Chemistry 010306 general physics 0210 nano-technology Supercooling |
| Zdroj: | The Journal of Physical Chemistry Letters. 9:3008-3013 |
| ISSN: | 1948-7185 |
| DOI: | 10.1021/acs.jpclett.8b01074 |
| Popis: | 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. 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. |
| Databáze: | OpenAIRE |
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