Combined description of pressure–volume–temperature and dielectric relaxation of several polymeric and low-molecular-weight organic glass-formers using SL-TS2 approach

Ginzburg, Valeriy V.; Zaccone, Alessio; Casalini, R.

doi:10.1039/d2sm01049f

Cited by 8 publications

(13 citation statements)

References 101 publications

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“…We adopted the two-state SL-TS2 formalism that combines the description of the density and relaxation time of an amorphous liquid or glassy material (see Ginzburg et al [ 45 , 47 , 48 ]). Within this model, water is considered as an ensemble comprised of two types of “clusters” (or cooperatively rearranging regions (CRRs)) (see Figure 7 ).…”

Section: Methodsmentioning

confidence: 99%

“…Recently, it was demonstrated that the Casalini-Roland scaling (Equation (15)) emerges naturally within the SL-TS2 framework (at least within some reasonably broad pressure range) [ 45 , 48 ]. Here, we follow the same idea.…”

Section: Methodsmentioning

confidence: 99%

“…Here, we follow the same idea. First, we assume that all of the temperature- and energy-type parameters ( ε * , E H , E L ) depend on the pressure, as follows:

where Y == ( ε * , E H , E L ), and α Τ =1/ P 0, T [ 48 ]. Note that Equation (16) implies that the energy-type parameters decrease upon increasing pressure; this is counterintuitive, but it seems to be the only way to describe the pressure dependence of the density-temperature curves.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, one of us proposed a two-state approach to describe the relaxation time and density of polymeric and low-molecular-weight glass-forming materials near their glass transition temperature [ 44 , 45 , 46 , 47 , 48 ]. Within this framework (labeled SL-TS2 approach), it is hypothesized that a glass-former is characterized by competition between two states with different activation energies, different mass, and different cohesive energy densities.…”

Section: Introductionmentioning

confidence: 99%

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Combined Description of the Equation of State and Diffusion Coefficient of Liquid Water Using a Two-State Sanchez–Lacombe Approach

2023

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Water is one of the most important compounds on Earth, yet its material properties are still poorly understood. Here, we use a recently developed two-state, two-(time)scale (TS2) dynamic mean-field model combined with the two-state Sanchez–Lacombe (SL) thermodynamic theory in order to describe the equation of state (density as a function of temperature and pressure) and diffusivity of liquid water. In particular, it is shown that in a relatively wide temperature and pressure range (160 K < T < 360 K; 0 < P < 100 MPa), density and self-diffusion obey a special type of dynamic scaling, similar to the “τTV” scaling of Casalini and Roland, but with the negative exponent γ. The model predictions are consistent with experimental data. The new equation of state can be used for various process models and generalized to include multicomponent mixtures.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…Here, we follow the same idea. First, we assume that all of the temperature- and energy-type parameters ( ε * , E H , E L ) depend on the pressure, as follows:

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Combined Description of the Equation of State and Diffusion Coefficient of Liquid Water Using a Two-State Sanchez–Lacombe Approach

2023

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“…Cohen et al utilized this concept to investigate the physical mechanism behind the liquid–glass transition of supercooled liquids . Subsequent thermodynamic models have confirmed the effectiveness of this two-state concept in characterizing the thermal properties of spin glasses and the retrograde vitrification of polymers with compressed fluid diluents. , More recently, Ginzburg et al proposed a “two-state, two-scale” (TS2) model, which has proven to be a powerful tool for characterizing the glassy dynamics of polymer thin films and random copolymers. − Motivated by these two-state approaches, we incorporate the concept of phase transition into the GD lattice model to characterize the relationship between the activation hopping behavior of local polymer segments and global multi-SME in multi-SMPs. Hole distribution in multi-SMPs is a function of time and temperature in the shape memory cycle, which is further investigated in the following section.…”

Section: Nonequilibrium Dynamic Modelmentioning

confidence: 99%

Spatially Heterogeneous Dynamics in Multi-Shape Memory Polymers Undergoing Broad Glass Transitions

Wang,

Li,

Zhang

et al. 2023

Macromolecules

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The purpose of this study is to present a nonequilibrium dynamic model for investigating the heterogeneous relaxation mechanism underlying the multi-shape memory effect (multi-SME) in amorphous polymers. By incorporating the concept of phase transition into the Gibbs−DiMarzio lattice model, a time-dependent hole distribution function is developed to characterize the heterogeneous dynamics and complex viscoelastic responses of multi-shape memory polymers (multi-SMPs) for the first time. The proposed formulation is employed in a multi-SME cycle under different thermomechanical loading histories. The excellent agreement between the numerical predictions and the available experimental results demonstrates the capability of the proposed approach to investigate dynamic heterogeneity and collective motion in multi-SMPs. The effects of the heating method, hole formation energy, and loading frequency on the relaxation spectrum and thermomechanical behavior of multi-SMPs are further investigated using the proposed model. It is found that the heterogeneous distribution and dynamical fluctuation of the holes in Nafion multi-SMPs lead to a broad glass transition range from 328 to 413 K. This study is expected to provide theoretical guidance for the design of amorphous polymers with tunable multi-SMEs, thereby facilitating practical applications.

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A perspective on the time‐dependent structure and properties of amorphous polymer

Juska

2024

SPE Polymers

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A molecular mechanism of viscoelastic deformation is presented. Amorphous polymers are characterized as a heterogeneous network of nanoscale cells. A “cell” is a homogeneous region within the network. Each cell phase fluctuates between the glassy and elastomer states with a period τ. The values of τ vary from cell to cell over several orders of magnitude and are strong functions of temperature. Whether a given cell responds as glassy or elastomeric depends on the ratio between its period of phase fluctuation (τj) and the period of observation (1/f), where f is the test frequency. We express this ratio, the Deborah number, as (τj × f), and present equations for modulus and energy loss as functions of (τj × f). The condition (τj × f) = 1 defines the glass transition of a cell, which arises cell‐by‐cell over a range of temperature, or over a range of time under stress. Viscoelastic deformation occurs if a cell changes phase while under stress. Energy stored during glassy state deformation is lost if the cell fluctuates to the elastomeric state. Stress is out of phase with strain, because strain rate controls the level of stress in glassy cells between phase fluctuations.Highlights A molecular mechanism of viscoelasticity is presented that does not involve viscous flow. Amorphous polymer is a heterogeneous network of nanoscale cells. Cells fluctuate in phase between glassy and elastomeric states due to their size. Time‐dependent properties are caused by time‐dependent structure. Energy is lost when glass phase cells under stress fluctuate to the elastomer phase.

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Combined description of pressure–volume–temperature and dielectric relaxation of several polymeric and low-molecular-weight organic glass-formers using SL-TS2 approach

Cited by 8 publications

References 101 publications

Combined Description of the Equation of State and Diffusion Coefficient of Liquid Water Using a Two-State Sanchez–Lacombe Approach

Combined Description of the Equation of State and Diffusion Coefficient of Liquid Water Using a Two-State Sanchez–Lacombe Approach

Spatially Heterogeneous Dynamics in Multi-Shape Memory Polymers Undergoing Broad Glass Transitions

A perspective on the time‐dependent structure and properties of amorphous polymer

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