Discharge of the Nanopore Confinement Effect on the Glass Transition Dynamics via Viscous Flow

Using dielectric spectroscopy, we demonstrate that confinement-induced changes in the glass transition dynamics, as observed for polymethylphenylsiloxane in alumina nanopores, reveal a pronounced nonequilibrium nature. Our results indicate that glass formers confined to nanopores are able to recover...

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Bibliographic Details
Published in:Physical review letters 2019-05, Vol.122 (17), p.176101-176101, Article 176101
Main Authors: Adrjanowicz, K, Paluch, M
Format: Article
Language:English
Subjects:
Aluminum oxide
Confinement
Flow velocity
Glass
Porosity
Time constant
Viscous flow
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Summary:Using dielectric spectroscopy, we demonstrate that confinement-induced changes in the glass transition dynamics, as observed for polymethylphenylsiloxane in alumina nanopores, reveal a pronounced nonequilibrium nature. Our results indicate that glass formers confined to nanopores are able to recover their bulklike mobility. We found that the characteristic time constant of such an equilibration process correlates with an extremely slow viscous flow rate in cylindrical channels of nanometer size. Thus, all the way to equilibrium, confinement effects seen in faster segmental dynamics are released through the viscous flow which eventually helps to eliminate surplus volume gained by nanoconstrained polymers upon cooling.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.122.176101