Phase behavior and concentration fluctuations in suspensions of hard spheres and nearly ideal polymers

2003 ◽  
Vol 118 (7) ◽  
pp. 3350-3361 ◽  
Author(s):  
S. A. Shah ◽  
Y. L. Chen ◽  
K. S. Schweizer ◽  
C. F. Zukoski
Keyword(s):  
Phase Behavior ◽  
Hard Spheres ◽  
Concentration Fluctuations

scholarly journals Effects of Polydispersity on the Phase Behavior of Additive Hard Spheres in Solution

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1543
Author(s):  
Luka Sturtewagen ◽  
Erik van der Linden
Keyword(s):  
Phase Behavior ◽  
Critical Point ◽  
Volume Fraction ◽  
Hard Spheres ◽  
Second Virial Coefficient ◽  
Two Phase ◽  
Different Types ◽  
Asymmetric Partitioning ◽  
Average Size ◽  
Liquid Liquid Phase Separation

The ability to separate enzymes, nucleic acids, cells, and viruses is an important asset in life sciences. This can be realised by using their spontaneous asymmetric partitioning over two macromolecular aqueous phases in equilibrium with one another. Such phases can already form while mixing two different types of macromolecules in water. We investigate the effect of polydispersity of the macromolecules on the two-phase formation. We study theoretically the phase behavior of a model polydisperse system: an asymmetric binary mixture of hard spheres, of which the smaller component is monodisperse and the larger component is polydisperse. The interactions are modelled in terms of the second virial coefficient and are assumed to be additive hard sphere interactions. The polydisperse component is subdivided into sub-components and has an average size ten times the size of the monodisperse component. We calculate the theoretical liquid–liquid phase separation boundary (the binodal), the critical point, and the spinodal. We vary the distribution of the polydisperse component in terms of skewness, modality, polydispersity, and number of sub-components. We compare the phase behavior of the polydisperse mixtures with their concomittant monodisperse mixtures. We find that the largest species in the larger (polydisperse) component causes the largest shift in the position of the phase boundary, critical point, and spinodal compared to the binary monodisperse binary mixtures. The polydisperse component also shows fractionation. The smaller species of the polydisperse component favor the phase enriched in the smaller component. This phase also has a higher-volume fraction compared to the monodisperse mixture.

scholarly journals Phase behavior of weakly polydisperse sticky hard spheres: Perturbation theory for the Percus-Yevick solution

2006 ◽  
Vol 125 (16) ◽  
pp. 164504 ◽  
Author(s):  
Riccardo Fantoni ◽  
Domenico Gazzillo ◽  
Achille Giacometti ◽  
Peter Sollich
Keyword(s):  
Perturbation Theory ◽  
Phase Behavior ◽  
Hard Spheres

scholarly journals Generic phase diagram of binary superlattices

2016 ◽  
Vol 113 (37) ◽  
pp. 10269-10274 ◽  
Author(s):  
Alexei V. Tkachenko
Keyword(s):  
Phase Diagram ◽  
Phase Behavior ◽  
Hard Spheres ◽  
General Procedure ◽  
Particle Size Ratio ◽  
System Composition ◽  
Wide Range ◽  
Self Assembled ◽  
Model Features ◽  
2D And 3D

Emergence of a large variety of self-assembled superlattices is a dramatic recent trend in the fields of nanoparticle and colloidal sciences. Motivated by this development, we propose a model that combines simplicity with a remarkably rich phase behavior applicable to a wide range of such self-assembled systems. Those systems include nanoparticle and colloidal assemblies driven by DNA-mediated interactions, electrostatics, and possibly, controlled drying. In our model, a binary system of large and small hard spheres (L and S, respectively) interacts via selective short-range (“sticky”) attraction. In its simplest version, this binary sticky sphere model features attraction only between S and L particles. We show that, in the limit when this attraction is sufficiently strong compared with kT, the problem becomes purely geometrical: the thermodynamically preferred state should maximize the number of LS contacts. A general procedure for constructing the phase diagram as a function of system composition f and particle size ratio r is outlined. In this way, the global phase behavior can be calculated very efficiently for a given set of plausible candidate phases. Furthermore, the geometric nature of the problem enables us to generate those candidate phases through a well-defined and intuitive construction. We calculate the phase diagrams for both 2D and 3D systems and compare the results with existing experiments. Most of the 3D superlattices observed to date are featured in our phase diagram, whereas several more are predicted for future discovery.

scholarly journals Eutectic liquid crystal mixture E7 in nanoporous alumina. Effects of confinement on the thermal and concentration fluctuations

RSC Advances ◽  
2019 ◽  
Vol 9 (65) ◽  
pp. 37846-37857 ◽  
Author(s):  
Aristoula Selevou ◽  
George Papamokos ◽  
Tolga Yildirim ◽  
Hatice Duran ◽  
Martin Steinhart ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Liquid Crystal ◽  
Phase Behavior ◽  
Concentration Fluctuations ◽  
Eutectic Liquid ◽  
Nanoporous Alumina ◽  
Crystal Mixture

Confinement of the eutectic compound E7 in AAO membranes alters its phase behavior, molecular dynamics and nature of N/I transition.

On the Concentration Fluctuations of a Binary Mixture of Hard Spheres

1988 ◽  
Vol 43 (10) ◽  
pp. 847-850 ◽  
Author(s):  
L. J. Gallego ◽  
J. A. Somoza ◽  
M. C. Blanco
Keyword(s):  
Phase Transition ◽  
Binary Mixture ◽  
Hard Sphere ◽  
Equations Of State ◽  
Hard Spheres ◽  
Fluid Phase ◽  
Packing Fraction ◽  
Concentration Fluctuations ◽  
Entropy Of Mixing ◽  
First Approximation

Abstract We have computed the concentration fluctuations, Scc(0), in a binary mixture of hard spheres on the basis of the Percus-Yevick compressibility (PYC), Percus-Yevick virial (PYV) and Mansoori- Carnahan-Starling (MCS) equations of state. We have also used the Flory-Huggins (FH) model for an athermal solution as a first approximation to the hard sphere description. At fluid packing fraction values, the PYC and MCS theories give similar Scc (0) results, whereas the differences between these and those derived from the PYV equation are more significant. The FH model appears to give rather bad results, which is consistent with the studies of other authors on the entropy of mixing of a binary mixture of hard spheres. The impossibility of a fluid-fluid phase transition in this kind of system is clearly shown by the behaviour of Scc (0) in any of the theories studied.

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