Nanoparticle motion within glassy polymer melts.
X-ray photon correlation spectroscopy is employed to investigate the motion of dilute suspensions of gold nanoparticles in low-molecular-weight polystyrene melts. At high temperatures, the observed motion is diffusive, with a rate that follows a Vogel-Fulcher temperature dependence. Closer to the glass transition temperature Tg, diffusion is superseded by a hyperdiffusive process that first becomes observable near a crossover temperature Tc approximately 1.1Tg and is identified with heterogeneous strain in the melts. Following rapid cooling to temperatures sufficiently below Tc, but still above Tg, the hyperdiffusive dynamics displays a time dependence similar to aging in polymer glasses.
Guo
Hongyu
H
Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Bourret
Gilles
G
Corbierre
Muriel K
MK
Rucareanu
Simona
S
Lennox
R Bruce
RB
Laaziri
Khalid
K
Piche
Luc
L
Sutton
Mark
M
Harden
James L
JL
Leheny
Robert L
RL