Isobaric and isochoric properties of decahydroisoquinoline, an extremely fragile glass-former

Casalini, R.; McGrath, K. J.; Roland, C. M.

doi:10.1016/j.jnoncrysol.2006.02.151

Cited by 18 publications

(13 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Actually, the existence of correlations between the scaling exponent and the fragility has previously been realized empirically. [8,12,37,38] In particular, two empirical correlations have been suggested by Casalini and Roland [12],…”

Section: Influence Of the Side Group Lengthmentioning

confidence: 97%

Thermodynamic scaling of dynamics in polymer melts: Predictions from the generalized entropy theory

Freed

2013

The Journal of Chemical Physics

View full text Add to dashboard Cite

Many glass-forming fluids exhibit a remarkable thermodynamic scaling in which dynamic properties, such as the viscosity, the relaxation time, and the diffusion constant, can be described under different thermodynamic conditions in terms of a unique scaling function of the ratio ρ γ /T , where ρ is the density, T is the temperature, and γ is a material dependent constant. Interest in the scaling is also heightened because the exponent γ enters prominently into considerations of the relative contributions to the dynamics from pressure effects (e.g., activation barriers) vs. volume effects (e.g., free volume). Although this scaling is clearly of great practical use, a molecular understanding of the scaling remains elusive. Providing this molecular understanding would greatly enhance the utility of the empirically observed scaling in assisting the rational design of materials by describing how controllable molecular factors, such as monomer structures, interactions, flexibility, etc., influence the scaling exponent γ and, hence, the dynamics. Given the successes of the generalized entropy theory in elucidating the influence of molecular details on the universal properties of glass-forming polymers, this theory is extended here to investigate the thermodynamic scaling in polymer melts. The predictions of theory are in accord with the appearance of thermodynamic scaling for pressures not in excess of ∼ 50 MPa. (The failure at higher pressures arises due to inherent limitations of a lattice model.) In line with arguments relating the magnitude of γ to the steepness of the repulsive part of the intermolecular potential, the abrupt, square-well nature of the lattice model interactions lead, as expected, to much larger values of the scaling exponent. Nevertheless, the theory is employed to study how individual molecular parameters affect the scaling exponent in order to extract a molecular understanding of the information content contained in the exponent. The chain rigidity, cohesive energy, chain length, and the side group length are all found to significantly affect the magnitude of the scaling exponent, and the computed trends agree well with available experiments. The variations of γ with these molecular parameters are explained by establishing a correlation between the computed molecular dependence of the scaling exponent and the fragility. Thus, the efficiency of packing the polymers is established as the universal physical mechanism determining both the fragility and the scaling exponent γ.

show abstract

Section: Influence Of the Side Group Lengthmentioning

confidence: 97%

Thermodynamic scaling of dynamics in polymer melts: Predictions from the generalized entropy theory

Freed

2013

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…The answer we obtained when we explored the question was that in some systems it does, while in others it does not. The idea has been greatly expanded upon (and was perhaps indirectly asked in early work by Williams [9]) particularly by Alba-Simionesco and co-workers [10,11] and Roland and co-workers [12][13][14][15] in elegant dielectric measurements over a large range of temperatures and pressures that show different Table 1 Isobaric and isochoric transition strengths from PVT data on polycarbonate showing that the strengths of the transition are greater for the isobaric glass-formation route than for the isochoric route (after Colucci et al [1]). …”

Section: Thermodynamic and Dynamic Fragilitiesmentioning

confidence: 99%

A brief discussion: Thermodynamic and dynamic fragilities, non-divergent dynamics and the Prigogine–Defay ratio

McKenna

2009

Journal of Non-Crystalline Solids

View full text Add to dashboard Cite

“…Previously, ρ(T, P) for DHIQ was reported for temperatures down to 298 K and pressures up to 0.2 GPa. 23 However, the dielectric measurements on DHIQ used to test density scaling 20 extend to lower T (∼181 K) and higher P (1.75 GPa). Thus, the application of Eq.…”

Section: Introductionmentioning

confidence: 99%

The “anomalous” dynamics of decahyroisoquinoline revisited

Casalini

Roland

2016

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

Decahydroisoquinoline (DHIQ) appears to be a unique material-the only non-associated, simple liquid with dynamics deviating from density scaling. To examine whether this anomaly is real, the density, ρ, of DHIQ was measured at temperatures, T, as low as 214 K and pressures up to ∼1.2 GPa. This enabled the equation of state (EoS) to be determined, without extrapolation, over the range of thermodynamic conditions for which the relaxation times had been reported. Using this less ambiguous EoS, we find that within the precision of the available relaxation times, the latter are a function of T/ρ(3.9), contrary to previous reports. Thus, the behavior of DHIQ is unexceptional; similar to every non-associated liquid tested to date, its dynamics comply with density scaling.

show abstract

Isobaric and isochoric properties of decahydroisoquinoline, an extremely fragile glass-former

Cited by 18 publications

References 45 publications

Thermodynamic scaling of dynamics in polymer melts: Predictions from the generalized entropy theory

Thermodynamic scaling of dynamics in polymer melts: Predictions from the generalized entropy theory

A brief discussion: Thermodynamic and dynamic fragilities, non-divergent dynamics and the Prigogine–Defay ratio

The “anomalous” dynamics of decahyroisoquinoline revisited

Contact Info

Product

Resources

About