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

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.

Structural and thermodynamic properties of fluids whose molecules interact via one-, two-, and three-step potentials

“…This is followed by Sec. 3, which contains the results of our calculations for illustrative cases and their comparison with the recent simulation data for such cases [11]. We close the paper in Sec.…”

“…1, the simulation results do not correspond to genuine discontinuous potentials but to continuous potentials that mimic the discontinuous ones (see Ref. [11] for details). The latter feature manifests itself in the fact that, in contrast to the RFA results, the RDF simulation data do not present jumps at r = λ j , as clearly seen in Fig.…”

“…In this section we illustrate the results of our approach by examining their performance against recent simula-tion data [11] for both the structural and thermodynamic properties of this kind of fluids. For this purpose, it is convenient to order the different systems according to the number of steps after the hard core, so that the label A will indicate a single SW, the label B a SW followed by a SS, and the label C a SW followed by a SS and a second SW.…”

“…In contrast, in the case of system C1, b 3,c becomes more accurate than b 3,v if T * > 1.24. Now we turn to the comparison with the recent sim-ulation data of Perdomo et al [11], starting with the structural properties. In Fig.…”

“…Very recently Perdomo-Pérez et al [11] have considered fluids with competing interactions modeled through a succession of SW and SS potentials. Their main goal was to systematically study the effect of each potential contribution on the physical properties of a competing interaction fluid.…”