Supercooled Liquids

Mohanty, Udayan

doi:10.1002/9780470141489.ch2

Cited by 29 publications

(9 citation statements)

References 278 publications

(401 reference statements)

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“…The T 0 parameter is approximately equal to the glass transition temperature (T g ) for fragile liquids, and is lower than T g for strong liquids. 59 In the current work, T 0 was found to be between 160 and 184 K, similar to values reported previously for other ILs 54, 60-62 and close to the experimentally measured T g . 63 as a function of both temperature and G4 composition.…”

Section: Experimental Methodssupporting

confidence: 91%

How mixing tetraglyme with the ionic liquid 1-n-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide changes volumetric and transport properties: An experimental and computational study

Sharma

Zhang

Gohndrone

et al. 2017

Chemical Engineering Science

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The viscosity and density of the ionic liquid (IL) 1-n-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C 6 mim][N T f 2 ]), the molecular solvent tetraethylene glycol dimethyl ether (tetraglyme or G4) and their binary mixtures were measured experimentally as a function of temperature. The same systems were also studied using classical molecular dynamics (MD) simulations. The viscosities of the [C 6 mim][N T f 2 ]/G4 mixtures decrease with increasing G4 concentration, though not as much as an ideal mixing model would predict. Detailed analysis of the MD results reveals that G4 preferentially solvates cations, leading to a reduction in the interaction energy between cations and anions and a subsequent enhancement in anion mobility. A similar effect has been reported when glymes are mixed with salts containing alkali metal cations, with the resulting mixtures being called "solvate" ionic liquids. The simulations predict that the ionic conductivity will be maximized when the G4 mole fraction is around 10-20%. The ability of G4 to effectively solvate the cations stems from localized charges on the oxygens. The simulations predict that solvents having large localized positive charges would preferentially solvate anions, leading to enhanced cation mobility.

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Section: Experimental Methodssupporting

confidence: 91%

How mixing tetraglyme with the ionic liquid 1-n-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide changes volumetric and transport properties: An experimental and computational study

Sharma

Zhang

Gohndrone

et al. 2017

Chemical Engineering Science

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“…If the identification S conf Х S exc is accepted, fragile liquids should have larger excess specific heat than strong liquids. This is traditionally reported as the general trend ͑Angell, 1985; Mohanty, 1995;Ito, Moynihan, and Angell, 1999;Xia and Wolynes, 2000͒, but even this conventional wisdom has recently been challenged ͑Ngai and Yamamuro, 1999;Huang and McKenna, 2001͒. As mentioned, the identification S conf Х S exc is problematic. This brings into question the experimental support for the entropy model, but why then do fragility and excess heat capacity appear to correlate?…”

Section: B the Thermodynamic Connectionmentioning

confidence: 99%

Colloquium: The glass transition and elastic models of glass-forming liquids

2006

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“…The two basic assumptions ,, in the Adam–Gibbs model are (i) the inverse relationship between the minimum number of molecules z * that allows cooperative rearrangements and the configurational entropy of the glass-forming liquid, and (ii) the number of molecules inside a cooperative rearranging volume is equal to the minimum number that undergoes independent rearrangements. The derivation leading to eq avoids both these assumptions.…”

Section: Discussionmentioning

confidence: 99%

“…The Adam–Gibbs model predicts a linear relation between log (experimental relaxation time) and ( TS c ) −1 . There have been various generalizations of the Adam–Gibbs model. − …”

Section: Introductionmentioning

confidence: 99%

Fluctuation Effects in the Adam–Gibbs Model of Cooperative Relaxation

et al. 2019

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A generalization of the Adam–Gibbs model of relaxation in glass-forming liquids is formulated that takes into account fluctuation in the number of molecules inside the cooperative region. The configurational fraction links the excess entropy with kinetic properties described in the Adam–Gibbs model. We express the configurational fraction at the glass-transition temperature in terms of the width of the distribution of relaxation times, the nonlinearity parameter that demarcates the variations of the relaxation time with structure and temperature, the steepness index that is proportional to the slope of the logarithm of the relaxation time with respect to temperature, the excess heat capacity under constant pressure, and the number of correlated molecules or structural units. The configurational fraction in the absence of fluctuation effects is also determined for several glass-forming liquids at the glass-transition temperature.

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Supercooled Liquids

Cited by 29 publications

References 278 publications

How mixing tetraglyme with the ionic liquid 1-n-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide changes volumetric and transport properties: An experimental and computational study

How mixing tetraglyme with the ionic liquid 1-n-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide changes volumetric and transport properties: An experimental and computational study

Colloquium: The glass transition and elastic models of glass-forming liquids

Fluctuation Effects in the Adam–Gibbs Model of Cooperative Relaxation

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