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Microscopic Chain Motion in Polymer Nanocomposites with Dynamically Asymmetric Interphases
Erkan Senses1,2, Antonio Faraone1, Pinar Akcora3
1NIST Center for Neutron Research, National Institute of Standards and Technology Gaithersburg, MD 20899-8562, USA.
Scientific Reports
|July 27, 2016
Summary
The dynamics of polymers near nanoparticles significantly impact nanocomposite properties. A glassy interfacial polymer slows matrix chain dynamics, affecting material stiffening.
Area of Science:
- Polymer Science
- Materials Science
- Nanotechnology
Background:
- The rheological properties of polymer nanocomposites are influenced by the dynamics of polymers at the interface between nanoparticles and the matrix.
- Understanding these interfacial dynamics is crucial for designing advanced materials.
Purpose of the Study:
- To investigate the role of interfacial polymer dynamics on the segmental and collective dynamics of matrix polymer chains in nanocomposites.
- To explore how the state (glassy or rubbery) of the interfacial polymer affects matrix chain dynamics and macroscopic properties.
Main Methods:
- Neutron scattering investigations utilizing selective isotope labeling.
- Studying polymer dynamics across a time scale from subnanoseconds to 100 nanoseconds.
Main Results:
- Rouse relaxation of matrix chains is unaffected in weakly attractive systems.
- Dynamics significantly slow down in strongly attractive composites.
- Interfacial polymer disentanglement and increased reptation tube size observed when the bound polymer is in a glassy state.
Conclusions:
- The state of the bound polymer (glassy vs. rubbery) critically influences matrix chain dynamics.
- Interfacial polymer dynamics directly correlate with the macroscopic stiffening of polymer nanocomposites.
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