Thermodynamics, static properties and transport behaviour of fluids with competing interactions

2022 ◽  
Author(s):  
Roman Perdomo-Pérez ◽  
Jaime Martínez Rivera ◽  
Norma Caridad Palmero Cruz ◽  
Miguel Angel Sandoval Puentes ◽  
Javier Alejandro Sánchez Gallegos ◽  
...  
Keyword(s):  
Phase Behaviour ◽  
Model Systems ◽  
Static Properties ◽  
Competing Interactions ◽  
Intermediate Range Order ◽  
System Of Particles ◽  
Transport Behaviour ◽  
Square Well ◽  
Competing Interaction ◽  
Repulsive Forces

Abstract Competing interaction fluids have become ideal model systems to study a large number of phenomena, for example, the formation of intermediate range order structures, condensed phases not seen in fluids driven by purely attractive or repulsive forces, the onset of particle aggregation under in- and out-of-equilibrium conditions, which results in the birth of reversible and irreversible aggregates or clusters whose topology and morphology depend additionally on the thermodynamic constrictions, and a particle dynamics that has a strong influence on the transport behaviour and rheological properties of the fluid. In this contribution, we study a system of particles interacting through a potential composed by a continuous succession of a short-ranged square-well, an intermediate-ranged square-shoulder and a long-ranged square-well. This potential model is chosen to systematically analyse the contribution of every component of the interaction potential on the phase behaviour, the microstructure, the morphology of the resulting aggregates and the transport phenomena of fluids described by competing interactions. Our results indicate that the inclusion of a barrier and a second well leads to new and interesting effects, which in addition result in variations of the physical properties associated to the competition among interactions.

scholarly journals Phase Transitions in Nematic Fluids

2010 ◽  
Vol 2 (3) ◽  
pp. 419
Author(s):  
A. Oukouiss
Keyword(s):  
Solid Phase ◽  
Phase Behaviour ◽  
Isotropic Liquid ◽  
Rich Phase ◽  
First Order ◽  
Isotropic Solid ◽  
System Of Particles ◽  
Small Domain ◽  
Van Der Waals Theory ◽  
Anisotropic Interactions

We use a simple van der Waals theory, suitably extended to the solid phase and to anisotropic interactions, to study the phase behaviour of a system of particles with nematic interactions. Very rich phase behaviour is found which indicates, in particular, that the nematic liquid is stable only for large values of the strength of the nematic interactions. The isotropic liquid-nematic liquid and the isotropic solid-nematic solid transitions are always first-order. Additionally, we have found that the nematic liquid is thermodynamically stable only in a small domain of the temperature-density plane contained between two triple lines. Keywords:  Phase diagrams; Nematic interactions; Free energy; Transitions. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i3.4438                 J. Sci. Res. 2 (3), 419-432 (2010) 

scholarly journals Low-temperature antiferromagnetism of Ising model with competing interactions

2021 ◽  
pp. 64-71
Author(s):  
Kirill Tsiberkin ◽  
Keyword(s):  
Ising Model ◽  
Low Temperature ◽  
Temperature Shift ◽  
Second Order ◽  
Square Lattice ◽  
Antiferromagnetic Coupling ◽  
Competing Interactions ◽  
Saturation State ◽  
Spin Configuration ◽  
Competing Interaction

The paper presents a numerical analysis of equilibrium state and spin configuration of square lattice Ising model with competing interaction. The most detailed description is given for case of ferromagnetic interaction of the first-order neighbours and antiferromagnetic coupling of the second-order neighbours. The numerical method is based on Metropolis algorithm. It uses 128×128 lattice with periodic boundary conditions. At first, the simulation results show that the system is in saturation state at low temperatures, and it turns into paramagnetic state at the Curie point. The competing second-order interaction makes possible the domain structure realization. This state is metastable, because its energy is higher than saturation energy. The domains are small at low temperature, and their size increases when temperature is growing until the single domain occupies the whole simulation area. In addition, the antiferromagnetic coupling of the second-order neighbours reduces the Curie temperature of the system. If it is large enough, the lattice has no saturation state. It turns directly from the domain state into paramagnetic phase. There are no extra phases when the system is antiferromagnetic in main order, and only the Neel temperature shift realizes here.

scholarly journals Термодинамические и магнитные свойства двумерной анизотропной модели Изинга с конкурирующими взаимодействиями

2019 ◽  
Vol 61 (10) ◽  
pp. 1911
Author(s):  
А.К. Муртазаев ◽  
Ж.Г. Ибаев
Keyword(s):  
Exchange Interactions ◽  
Square Lattice ◽  
Wave Number ◽  
Two Dimensional ◽  
Competing Interactions ◽  
Distinctive Features ◽  
Magnetic Parameters ◽  
Modulated Structures ◽  
Temperature Dependences ◽  
Competing Interaction

The two-dimensional anisotropic Ising model was studied with competing interactions on a square lattice using Monte-Carlo methods using the Wang-Landau algorithm. The temperature dependences of the main thermodynamic and magnetic parameters are calculated. The distinctive features of the temperature dependences of these parameters are shown for different values of the competing interaction. The graphs of the dependence of the wave number of modulated structures on the ratio of the parameters of exchange interactions are plotted. Built phase diagram of the model. Interpolating the phase boundaries of the diagram, the coordinates of the Lifshchits point and phase localization areas with different wave vector values are calculated.

Fluorescent probe partitioning in giant unilamellar vesicles of ‘lipid raft’ mixtures

2010 ◽  
Vol 430 (3) ◽  
pp. 415-423 ◽  
Author(s):  
Janos Juhasz ◽  
James H. Davis ◽  
Frances J. Sharom
Keyword(s):  
Fluorescent Probe ◽  
Lipid Bilayer ◽  
Fluorescent Probes ◽  
Phase Behaviour ◽  
Model Systems ◽  
Fluorescence Probes ◽  
Lipid Phase ◽  
Giant Unilamellar Vesicles ◽  
Unilamellar Vesicles ◽  
Lipid Mixture

Direct visualization of raft-like lo (liquid-ordered) domains in model systems and cells using microscopic techniques requires fluorescence probes with known partitioning preference for one of the phases present. However, fluorescent probes may display dissimilar partitioning preferences in different lipid sys-tems and can also affect the phase behaviour of the host lipid bilayer. Therefore a detailed understanding of the behaviour of fluorescent probes in defined lipid bilayer systems with known phase behaviour is essential before they can be used for identifying domain phase states. Using giant unilamellar vesicles composed of the ternary lipid mixture DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine)/DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine)/cholesterol, for which the phase behaviour is known, we examined nine commonly used fluorescent probes using confocal fluorescence microscopy. The partitioning preference of each probe was assigned either on the basis of quantification of the domain area fractions or by using a well-characterized ld (liquid-disordered)-phase marker. Fluorescent probes were examined both individually and using dual or triple labelling approaches. Most of the probes partitioned individually into the ld phase, whereas only NAP (naphtho[2,3-a]pyrene) and NBD-DPPE [1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(7-nitro-2-1,3-benzoxadiazol-4-yl] preferred the lo phase. We found that Rh-DPPE (Lissamine™ rhodamine B–1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine) increased the miscibility transition temperature, Tmix. Interestingly, the partitioning of DiIC18 (1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate) was influenced by Bodipy®-PC [2-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl)-1-hexa-decanoyl-sn-glycero-3-phosphocholine]. The specific use of each of the fluorescent probes is determined by its photostability, partitioning preference, ability to detect lipid phase separations and induced change in Tmix. We demonstrate the importance of testing a specific fluorescent probe in a given model membrane system, rather than assuming that it labels a particular lipid phase.

Intermediate range order and structure in colloidal dispersions with competing interactions

2013 ◽  
Vol 139 (15) ◽  
pp. 154904 ◽  
Author(s):  
P. Douglas Godfrin ◽  
Ramón Castañeda-Priego ◽  
Yun Liu ◽  
Norman J. Wagner
Keyword(s):  
Colloidal Dispersions ◽  
Range Order ◽  
Competing Interactions ◽  
Intermediate Range ◽  
Intermediate Range Order

scholarly journals Influence of sucrose on the phase behaviour of phospholipid model systems

2021 ◽  
Vol 1762 (1) ◽  
pp. 012012
Author(s):  
Z Slavkova ◽  
N Drinova ◽  
H Chamati ◽  
J Genova
Keyword(s):  
Phase Behaviour ◽  
Model Systems

scholarly journals Stochastic Model for Energy Propagation in Disordered Granular Chains

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1815
Author(s):  
Kianoosh Taghizadeh ◽  
Rohit Shrivastava ◽  
Stefan Luding
Keyword(s):  
Energy Transfer ◽  
Stochastic Model ◽  
Initial Conditions ◽  
Energy Levels ◽  
Model Systems ◽  
Energy Localization ◽  
Ensemble Averaging ◽  
Energy Propagation ◽  
Granular Chains ◽  
Repulsive Forces

Energy transfer is one of the essentials of mechanical wave propagation (along with momentum transport). Here, it is studied in disordered one-dimensional model systems mimicking force-chains in real systems. The pre-stressed random masses (other types of disorder lead to qualitatively similar behavior) interact through (linearized) Hertzian repulsive forces, which allows solving the deterministic problem analytically. The main goal, a simpler, faster stochastic model for energy propagation, is presented in the second part, after the basic equations are re-visited and the phenomenology of pulse propagation in disordered granular chains is reviewed. First, the propagation of energy in space is studied. With increasing disorder (quantified by the standard deviation of the random mass distribution), the attenuation of pulsed signals increases, transiting from ballistic propagation (in ordered systems) towards diffusive-like characteristics, due to energy localization at the source. Second, the evolution of energy in time by transfer across wavenumbers is examined, using the standing wave initial conditions of all wavenumbers. Again, the decay of energy (both the rate and amount) increases with disorder, as well as with the wavenumber. The dispersive ballistic transport in ordered systems transits to low-pass filtering, due to disorder, where localization of energy occurs at the lowest masses in the chain. Instead of dealing with the too many degrees of freedom or only with the lowest of all the many eigenmodes of the system, we propose a stochastic master equation approach with reduced complexity, where all frequencies/energies are grouped into bands. The mean field stochastic model, the matrix of energy-transfer probabilities between bands, is calibrated from the deterministic analytical solutions by ensemble averaging various band-to-band transfer situations for short times, as well as considering the basis energy levels (decaying with the wavenumber increasing) that are not transferred. Finally, the propagation of energy in the wavenumber space at transient times validates the stochastic model, suggesting applications in wave analysis for non-destructive testing, underground resource exploration, etc.

scholarly journals Theory for the phase behaviour of a colloidal fluid with competing interactions

2008 ◽  
Vol 20 (41) ◽  
pp. 415106 ◽  
Author(s):  
A J Archer ◽  
C Ionescu ◽  
D Pini ◽  
L Reatto
Keyword(s):  
Phase Behaviour ◽  
Competing Interactions

Perturbation theory of non-polar convex molecule fluids

1981 ◽  
Vol 46 (6) ◽  
pp. 1355-1364 ◽  
Author(s):  
Tomáš Boublík
Keyword(s):  
Correlation Function ◽  
Thermodynamic Functions ◽  
Hard Spheres ◽  
Convex Bodies ◽  
Pair Potential ◽  
Second Order ◽  
Phase Behaviour ◽  
Order Perturbation ◽  
Perturbation Term ◽  
Repulsive Forces

The second-order perturbation expansion is proposed for describing the equilibrium behaviour of non-polar fluids whose intermolecular interactions are expressed by the Kihara non-central pair potential. The definition of the predominant action range of the attractive and repulsive forces as well as the expression for the first-order perturbation term correspond to the WCA formulation for particles with central interactions; to determine the second-order perturbation term the extended macroscopic compressibility approximation is used. The system of soft convex bodies parallel to molecule cores is taken as the reference system; its equilibrium behaviour is described by thermodynamic functions of representative hard convex bodies with temperature and density dependent thickness. For calculating these functions, a very accurate equation of state was used; the average correlation function was approximated on the basis of the correlation function of corresponding hard spheres. The perturbation method was used for determining thermodynamic functions of nitrogen and for studying its phase behaviour; the calculated coexistence curve is compared with experiment.

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