Correlation between fragility and cooperativity in segmental dynamics of glass-forming para-substituted polystyrenes
نویسندگان
چکیده
منابع مشابه
Fragility and thermodynamics in nonpolymeric glass-forming liquids.
For nonpolymeric supercooled liquids, the empirical correlation m = 56Tg DeltaCp(Tg)/DeltaHm provides a reliable means of correlating dynamic and thermodynamic variables. The dynamics are characterized by the fragility or steepness index m and the glass transition temperature Tg, while thermodynamics enter in terms of the heat capacity step DeltaCp at Tg and the melting enthalpy DeltaHm. The co...
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The relation between fragility and cooperativity of atomic motion in bulk metallic glass forming liquids is studied based on the bond strength-coordination number fluctuation model. The model describes the temperature dependence of the viscosity in terms of the mean values of the bond strength, coordination number and their fluctuations of the structural units that form the melt. According to t...
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In contrast to pure metals and most non-glass forming alloys, metallic glass-formers are moderately strong liquids in terms of fragility. The notion of fragility of an undercooling liquid reflects the sensitivity of the viscosity of the liquid to temperature changes and describes the degree of departure of the liquid kinetics from the Arrhenius equation. In general, the fragility of metallic gl...
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– The utility of a cooperative length scale for describing the dynamics of small molecule glass-formers is shown. Molecular Dynamics and Monte Carlo simulations reveal a distribution of cooperatively moving fractal events below the temperature TA at which dynamics become caged. Guided by these results, four straightforward methods emerge to recognize TA in experimental data and quantify the len...
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α-Fluoroalcohols have been proposed as transparent, base-soluble functional groups for use in the design of new 157 nm photoresist polymers. The two most common and easily prepared fluoroisopropanol groups are bis-trifluoromethyl carbinols (hexafluoroalcohol) and methyl-trifluoromethyl carbinols (trifluoroalcohol). This paper describes studies designed to assess the suitability of both of these...
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ژورنال
عنوان ژورنال: Polymer Journal
سال: 2015
ISSN: 0032-3896,1349-0540
DOI: 10.1038/pj.2015.50