Pressure-Induced Glass Transition Probed via the Mobility of Coumarin 1 Fluorescent Molecule

Marco Bonetti 1
1 SPHYNX - Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes
SPEC - UMR3680 - Service de physique de l'état condensé, IRAMIS - Institut Rayonnement Matière de Saclay
Abstract : The route to form a glass is generally achieved upon cooling where the slowing down might be interpreted as the trapping of molecules in potential wells. On the other hand, isothermal compression induces a glassy state by modifying the molecular packing ending in jamming. Here, we focus on how isothermal compression perturbs the mobility of a probe molecule in 3 different host liquids up to the pressure-induced glass transition. By fluorescence recovery technique the diffusion of the fluorescent molecule Coumarin 1 (C1) is measured in poly(propylene glycol) (PPG-1000M and -2700 M), in the fragile van der Waals propylene carbonate (PC), and in hydrogen-bonded methanol and ethanol. High pressures up to 6 GPa are obtained with a diamond anvil cell. In PC at a pressure ~1.3 GPa close to the glass-transition pressure the diffusion coefficient of C1 follows an Arrhenius behavior with a ~ 5-order magnitude increase of the diffusive time. No decoupling from the Stokes-Einstein equation is noticed. A similar exponential behavior is measured in ethanol and methanol but extended to different pressure ranges up to 2.5 and 6.2 GPa, respectively. In PPG-1000M a decoupling from the Stokes-Einstein relation is observed between 0.3 and 0.8 GPa that could be related to a modification of the interaction between polymer segments and the probe molecule. These results might indicate that interaction between probe and dynamic heterogeneities become less important under applied pressure, unlike in the temperature induced glass transition.
Type de document :
Article dans une revue
Journal of Physical Chemistry B, American Chemical Society, 2016, 120 (18), pp.4319 - 4328. 〈10.1021/acs.jpcb.6b02004〉
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Soumis le : lundi 6 mars 2017 - 14:26:29
Dernière modification le : jeudi 15 mars 2018 - 15:07:02

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Marco Bonetti. Pressure-Induced Glass Transition Probed via the Mobility of Coumarin 1 Fluorescent Molecule. Journal of Physical Chemistry B, American Chemical Society, 2016, 120 (18), pp.4319 - 4328. 〈10.1021/acs.jpcb.6b02004〉. 〈cea-01483775〉

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