Aggregate model of liquids

Abstract

Articles you may be interested inMelting of α-Al2O3 and vitrification of the undercooled alumina liquid: Ab initio vibrational calculations and their thermodynamic implications J. Chem. Phys. 138, 064507 (2013); 10.1063/1.4790612 Microscopic structure and thermodynamics of a core-softened model fluid: Insights from grand canonical Monte Carlo simulations and integral equations theoryAtomic-force pictures reveal a heterogeneous microstructure at the surface of glassy layers which should be similar to one of the many equivalent microstructures a liquid is running through. These microstructures are described with the aid of a kinetic model of reversible aggregation which goes back to formulations as used in the description of living polymerization or aggregation of polymers in solution. Aggregates are considered as dynamic subsystems wherein collective modes of motions are excited. Fluctuations of the aggregates, densely packed in a disordered pattern, leads to a broad size distribution which happens to be controlled by Boltzmann's factor. The disordered structure within the aggregates themselves is optimized, reduced aggregate energy and entropy should be equal. Symmetries are deduced which elucidate many universal properties of the dynamic microstructure of liquids. Thermodynamic properties like the specific heats of aggregation in liquids or the dependence of the glass transition of homologues of linear atactic polystyrene are consistently described.

Polylactide/poly(hydroxybutyrate-co-hydroxyvalerate) blends: Morphology and mechanical properties

“…The model has successfully been applied to different objects and processes, including analysis of morphology of incompatible polymer blends [24][25][26][27][28]. In the model, statistical distribution h(s) of the planar size s of the microstructural entities can be read as Equation (1) [22,23]: (1) where a is the normalizing parameter and !u 0 is the aggregation energy. The latter parameter can be treated as a potential barrier to be overcome for the formation of a statistical ensemble.…”

“…For statistical analysis of the size distributions of dispersed-phase particles we used the model of the reversible aggregation [22,23]. The model is based on principles of irreversible thermodynamics and describes microstructure evolution in liquids.…”

“…The obtained images were segmented and processed by digital analysis using UTHSCSA ImageTool 3.0 software (Health Science Center, the University of Texas, San Antonio, USA) resulting in histograms describing minor phase particle size distribution. The histograms were consequently described using the model of reversible aggregation [22,23].…”

Recognition and Statistical Size Distribution of Microdomains in Tem-Images of Polyimide Films During Their Processing

“…Micro-domains observed at the surface of PAA films all along their conversion (under heating) to PI were analysed with the model of reversible aggregation (Kilian et al, 1997;Köpf and Kilian, 1999). This model describes stationary ensemble properties whose characteristics are evaluated.…”

“…The number of unit-to-unit contacts y in an aggregate is defined as y = y a -1. The aggregation energy ∆u [J] should therefore grow proportional to y: (Kilian et al, 1997(Kilian et al, , 2001Köpf and Kilian, 1999):…”