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Opdam J, Peters VFD, Wensink HH, Tuinier R. Multiphase Coexistence in Binary Hard Colloidal Mixtures: Predictions from a Simple Algebraic Theory. J Phys Chem Lett 2023; 14:199-206. [PMID: 36580685 PMCID: PMC9841575 DOI: 10.1021/acs.jpclett.2c03138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A general theoretical framework is proposed to quantify the thermodynamic properties of multicomponent hard colloidal mixtures. This framework is used to predict the phase behavior of mixtures of rods with spheres and rods with plates taking into account (liquid) crystal phases of both components. We demonstrate a rich and complex range of phase behaviors featuring a large variety of different multiphase coexistence regions, including two five-phase coexistence regions for hard rod/sphere mixtures, and even a six-phase equilibrium for hard rod/plate dispersions. The various multiphase coexistences featured in a particular mixture are in line with a recently proposed generalized phase rule and can be tuned through subtle variations of the particle shape and size ratio. Our approach qualitatively accounts for certain multiphase equilibria observed in rod/plate mixtures of clay colloids and will be a useful guide in tuning the phase behavior of shape-disperse mixtures in general.
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Affiliation(s)
- J. Opdam
- Laboratory
of Physical Chemistry, Department of Chemical Engineering and Chemistry,
and Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, 5600 MBEindhoven, The Netherlands
| | - V. F. D. Peters
- Laboratory
of Physical Chemistry, Department of Chemical Engineering and Chemistry,
and Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, 5600 MBEindhoven, The Netherlands
- Department
of Earth Sciences, Utrecht University, Princetonlaan 8a, 3584CBUtrecht, The Netherlands
| | - H. H. Wensink
- Laboratoire
de Physique des Solides, Université Paris-Saclay and CNRS, 91405Orsay, France
| | - R. Tuinier
- Laboratory
of Physical Chemistry, Department of Chemical Engineering and Chemistry,
and Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, 5600 MBEindhoven, The Netherlands
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2
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Miyazaki K, Schweizer KS, Thirumalai D, Tuinier R, Zaccarelli E. The Asakura–Oosawa theory: Entropic forces in physics, biology, and soft matter. J Chem Phys 2022; 156:080401. [DOI: 10.1063/5.0085965] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- K. Miyazaki
- Department of Physics, Nagoya University, Nagoya 464-8602, Japan
| | - K. S. Schweizer
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
- Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
- Department of Materials Science, University of Illinois, Urbana, Illinois 61801, USA
| | - D. Thirumalai
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, USA
| | - R. Tuinier
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - E. Zaccarelli
- CNR-ISC (National Research Council–Institute for Complex Systems) and Department of Physics, Sapienza University of Rome, Rome, Italy
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Peters VD, González García Á, Wensink HH, Vis M, Tuinier R. Multiphase Coexistences in Rod-Polymer Mixtures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:11582-11591. [PMID: 34553593 PMCID: PMC8495896 DOI: 10.1021/acs.langmuir.1c01896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/09/2021] [Indexed: 06/13/2023]
Abstract
Using recently derived analytical equations of state for hard rod dispersions, we predict the phase behavior of athermal rod-polymer mixtures with free volume theory. The rods are modeled as hard spherocylinders, while the nonadsorbing polymer chains are described as penetrable hard spheres. It is demonstrated that all of the different types of phase states that are stable for pure colloidal rod dispersions can coexist with any combination of these phases if polymers are added, depending on the concentrations, rod aspect ratio, and polymer-rod size ratio. This includes novel two-, three-, and four-phase coexistences and isostructural coexistences between dilute and concentrated phases of the same kind, even for the more ordered (liquid) crystal phases. This work provides insight into the conditions at which particular multiphase coexistences are expected for well-defined model colloidal rod-polymer mixtures. We provide a quantitative map detailing the various types of isostructural coexistences, which confirms an early qualitative hypothesis by Bolhuis et al. ( J. Chem. Phys. 107, 1997 1551).
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Affiliation(s)
- Vincent
F. D. Peters
- Laboratory
of Physical Chemistry, Department of Chemical Engineering and Chemistry
& Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Álvaro González García
- Sustainable
Polymer Chemistry Group, Department of Molecules & Materials, MESA + Institute for Nanotechnology, University of
Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Henricus H. Wensink
- Laboratoire
de Physique des Solides − UMR 8502, CNRS & Université
Paris-Saclay, 91400 Orsay, France
| | - Mark Vis
- Laboratory
of Physical Chemistry, Department of Chemical Engineering and Chemistry
& Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Remco Tuinier
- Laboratory
of Physical Chemistry, Department of Chemical Engineering and Chemistry
& Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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Sturtewagen L, van der Linden E. Effects of Polydispersity on the Phase Behavior of Additive Hard Spheres in Solution. Molecules 2021; 26:1543. [PMID: 33799773 PMCID: PMC7999821 DOI: 10.3390/molecules26061543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/25/2021] [Accepted: 02/28/2021] [Indexed: 11/16/2022] Open
Abstract
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.
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Affiliation(s)
- Luka Sturtewagen
- Laboratory of Physics and Physical Chemistry of Foods, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands;
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D’Adamo G, Pelissetto A, Pierleoni C. Phase Diagram and Structure of Mixtures of Large Colloids and Linear Polymers under Good-Solvent Conditions. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00600] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Andrea Pelissetto
- Dipartimento di Fisica, Sapienza Università di Roma and INFN, Sezione di Roma I, P.le Aldo Moro
2, I-00185 Rome, Italy
| | - Carlo Pierleoni
- Dipartimento di Scienze Fisiche
e Chimiche, Università dell’Aquila, V. Vetoio 10, Loc. Coppito, I-67100 L’Aquila, Italy
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López de Haro M, Tejero CF, Santos A, Yuste SB, Fiumara G, Saija F. Virial coefficients and demixing in the Asakura–Oosawa model. J Chem Phys 2015; 142:014902. [DOI: 10.1063/1.4904891] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Mariano López de Haro
- Instituto de Energías Renovables, Universidad Nacional Autónoma de México (U.N.A.M.), Temixco, Morelos 62580, Mexico
| | - Carlos F. Tejero
- Facultad de Ciencias Físicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | - Andrés Santos
- Departamento de Física and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, E-06071 Badajoz, Spain
| | - Santos B. Yuste
- Departamento de Física and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, E-06071 Badajoz, Spain
| | - Giacomo Fiumara
- Department of Mathematics and Computer Science, University of Messina, Viale F. Stagno D’Alcontres 31, I-98166 Messina, Italy
| | - Franz Saija
- CNR-IPCF, Viale F. Stagno d’Alcontres, 37-98158 Messina, Italy
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D'Adamo G, Pelissetto A, Pierleoni C. Phase diagram of mixtures of colloids and polymers in the thermal crossover from good to θ solvent. J Chem Phys 2014; 141:024902. [PMID: 25028041 DOI: 10.1063/1.4885818] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We determine the phase diagram of mixtures of spherical colloids and neutral nonadsorbing polymers in the thermal crossover region between the θ point and the good-solvent regime. We use the generalized free-volume theory, which takes into account the polymer-concentration dependence of the depletion thickness and of the polymer compressibility. This approach turns out to be quite accurate as long as q = Rg/Rc ≲ 1 (Rg is the radius of gyration of the polymer and Rc is the colloid radius). We find that, close to the θ point, the phase diagram is not very sensitive to solvent quality, while, close to the good-solvent region, changes of the solvent quality modify significantly the position of the critical point and of the binodals. We also analyze the phase behavior of aqueous solutions of charged colloids and polymers, using the approach proposed by Fortini et al. [J. Phys.: Condens. Matter 17, 7783 (2005)].
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Affiliation(s)
| | - Andrea Pelissetto
- Dipartimento di Fisica, Sapienza Università di Roma and INFN, Sezione di Roma I, P.le Aldo Moro 2, I-00185 Roma, Italy
| | - Carlo Pierleoni
- Dipartimento di Scienze Fisiche e Chimiche, Università dell'Aquila and CNISM, UdR dell'Aquila, V. Vetoio 10, Loc. Coppito, I-67100 L'Aquila, Italy
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8
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Woodward CE, Forsman J. Many-body interactions between particles in a polydisperse polymer fluid. J Chem Phys 2012; 136:084903. [DOI: 10.1063/1.3685834] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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9
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Annunziata MA, Pelissetto A. Fluid–fluid demixing curves for colloid–polymer mixtures in a random colloidal matrix. Mol Phys 2011. [DOI: 10.1080/00268976.2011.622724] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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10
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Lu B, Denton AR. Crowding of polymer coils and demixing in nanoparticle-polymer mixtures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:285102. [PMID: 21709352 DOI: 10.1088/0953-8984/23/28/285102] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The Asakura-Oosawa-Vrij (AOV) model of colloid-polymer mixtures idealises nonadsorbing polymers as effective spheres that are fixed in size and impenetrable to hard particles. Real polymer coils, however, are intrinsically polydisperse in size (radius of gyration) and may be penetrated by smaller particles. Crowding by nanoparticles can affect the size distribution of polymer coils, thereby modifying effective depletion interactions and thermodynamic stability. To analyse the influence of crowding on polymer conformations and demixing phase behaviour, we adapt the AOV model to mixtures of nanoparticles and ideal, penetrable polymer coils that can vary in size. We perform Gibbs ensemble Monte Carlo simulations, including trial nanoparticle-polymer overlaps and variations in the radius of gyration. Results are compared with predictions of free-volume theory. Simulation and theory consistently predict that ideal polymers are compressed by nanoparticles, and that compressibility and penetrability stabilise nanoparticle-polymer mixtures.
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Affiliation(s)
- Ben Lu
- Department of Physics, North Dakota State University, Fargo, ND 58108-6050, USA
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11
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12
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13
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Paricaud P. Phase equilibria in polydisperse nonadditive hard-sphere systems. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 78:021202. [PMID: 18850822 DOI: 10.1103/physreve.78.021202] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Indexed: 05/26/2023]
Abstract
Colloidal particles naturally exhibit a size polydispersity that can greatly influence their phase behavior in solution. Nonadditive hard-sphere (NAHS) mixtures are simple and well-suited model systems to represent phase transitions in colloid systems. Here, we propose an analytical equation of state (EOS) for NAHS fluid mixtures, which can be straightforwardly applied to polydisperse systems. For positive values of the nonadditivity parameter Delta the model gives accurate predictions of the simulated fluid-fluid coexistence curves and compressibility factors. NPT Monte Carlo simulations of the mixing properties of the NAHS symmetric binary mixture with Delta>0 are reported. It is shown that the enthalpy of mixing is largely positive and overcomes the positive entropy of mixing when the pressure is increased, leading to a fluid-fluid phase transition with a lower critical solution pressure. Phase equilibria in polydisperse systems are predicted with the model by using the density moment formalism [P. Sollich, Adv. Chem. Phys. 116, 265 (2001)]. We present predictions of the cloud and shadow curves for polydisperse NAHS systems composed of monodisperse spheres and polydisperse colloid particles. A fixed nonadditivity parameter Delta > 0 is assumed between the monodisperse and polydisperse spheres, and a Schulz distribution is used to represent the size polydispersity. Polydispersity is found to increase the extent of the immiscibility region. The predicted cloud and shadow curves depend dramatically on the upper cutoff diameter sigmac of the Schulz distribution, and three-phase equilibria can occur for large values of sigmac.
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Affiliation(s)
- Patrice Paricaud
- Laboratoire de Chimie et Procédés, ENSTA, ParisTech, 32 Bd Victor, 75739, Paris cedex 15, France.
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14
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Hlushak SP, Kalyuzhnyi YV, Cummings PT. Phase coexistence in polydisperse athermal polymer-colloidal mixture. J Chem Phys 2008; 128:154907. [DOI: 10.1063/1.2907723] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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15
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Grodon C, Roth R. Multiphase coexistence in polydisperse colloidal mixtures. J Chem Phys 2007; 126:054901. [PMID: 17302501 DOI: 10.1063/1.2430524] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The authors study the phase behavior of mixtures of monodisperse colloidal spheres with a depletion agent which can have arbitrary shape and can possess a polydisperse size or shape distribution. In the low concentration limit considered here, the authors can employ the free-volume theory and take the geometry of particles of the depletion agent into account within the framework of fundamental measure theory. The authors apply their approach to study the phase diagram of a mixture of (monodisperse) colloidal spheres and two polydisperse polymer components. By fine tuning the distribution of the polymer, it is possible to construct a complex phase diagram which exhibits two stable critical points.
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Affiliation(s)
- C Grodon
- Max-Planck-Institut für Metallforschung, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
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16
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Largo J, Wilding NB. Influence of polydispersity on the critical parameters of an effective-potential model for asymmetric hard-sphere mixtures. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:036115. [PMID: 16605606 DOI: 10.1103/physreve.73.036115] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Indexed: 05/08/2023]
Abstract
We report a Monte Carlo simulation study of the properties of highly asymmetric binary hard-sphere mixtures. This system is treated within an effective fluid approximation in which the large particles interact through a depletion potential [R. Roth, Phys. Rev. E 62 5360 (2000)] designed to capture the effects of a virtual sea of small particles. We generalize this depletion potential to include the effects of explicit size dispersity in the large particles and consider the case in which the particle diameters are distributed according to a Schulz form having a degree of polydispersity 14%. The resulting alteration (with respect to the monodisperse limit) of the metastable fluid-fluid critical point parameters is determined for two values of the ratio of the diameters of the small and large particles: q(triple bond)sigma(s)/(-)sigma(b)=0.1 and q=0.05. We find that the inclusion of polydispersity moves the critical point to lower reservoir volume fractions of the small particles and high volume fractions of the large ones. The estimated critical point parameters are found to be in good agreement with those predicted by a generalized corresponding states argument which provides a link to the known critical adhesion parameter of the adhesive hard-sphere model. Finite-size scaling estimates of the cluster percolation line in the one phase fluid region indicate that inclusion of polydispersity moves the critical point deeper into the percolating regime. This suggests that phase separation is more likely to be preempted by dynamical arrest in polydisperse systems.
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Affiliation(s)
- Julio Largo
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom
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Zhang Z, van Duijneveldt JS. Experimental phase diagram of a model colloid-polymer mixture in the protein limit. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:63-6. [PMID: 16378401 DOI: 10.1021/la0520637] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Sterically stabilized silica nanoparticles were synthesized, and turbidity measurements confirmed that they behaved as hard spheres in cyclohexane. Poly(isoprene) was added to give mixtures in the protein limit with a polymer coil/colloid radius ratio of 4.8. Their phase behavior under good solvent conditions was studied experimentally. The critical colloid volume fraction was phi = 0.13, whereas recent simulations (Bolhuis, P. G.; Meijer, E. J.; Louis, A. A. Phys. Rev. Lett. 2003, 90, 068304) predicted phi = 0.24. This difference is ascribed to the fact that many systems showing good solvent scaling behavior of the polymer still have a Flory-Huggins parameter close to 0.5, for instance, chi = 0.45 in this work.
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Affiliation(s)
- Zexin Zhang
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, England
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18
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Denton AR, Schmidt M. Mixtures of charged colloid and neutral polymer: Influence of electrostatic interactions on demixing and interfacial tension. J Chem Phys 2005; 122:244911. [PMID: 16035820 DOI: 10.1063/1.1940055] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The equilibrium phase behavior of a binary mixture of charged colloids and neutral, nonadsorbing polymers is studied within free-volume theory. A model mixture of charged hard-sphere macroions and ideal, coarse-grained, effective-sphere polymers is mapped first onto a binary hard-sphere mixture with nonadditive diameters and then onto an effective Asakura-Oosawa model [S. Asakura and F. Oosawa, J. Chem. Phys. 22, 1255 (1954)]. The effective model is defined by a single dimensionless parameter-the ratio of the polymer diameter to the effective colloid diameter. For high salt-to-counterion concentration ratios, a free-volume approximation for the free energy is used to compute the fluid phase diagram, which describes demixing into colloid-rich (liquid) and colloid-poor (vapor) phases. Increasing the range of electrostatic interactions shifts the demixing binodal toward higher polymer concentration, stabilizing the mixture. The enhanced stability is attributed to a weakening of polymer depletion-induced attraction between electrostatically repelling macroions. Comparison with predictions of density-functional theory reveals a corresponding increase in the liquid-vapor interfacial tension. The predicted trends in phase stability are consistent with observed behavior of protein-polysaccharide mixtures in food colloids.
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Affiliation(s)
- Alan R Denton
- Department of Physics, North Dakota State University, Fargo, 58105-5566, USA.
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19
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Aarts DGAL. Capillary Length in a Fluid−Fluid Demixed Colloid−Polymer Mixture. J Phys Chem B 2005; 109:7407-11. [PMID: 16851848 DOI: 10.1021/jp044312q] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We report measurements of the interfacial profile close to a vertical wall in a fluid-fluid demixed colloid-polymer mixture. The profile is measured by means of laser scanning confocal microscopy. It is accurately described by the interplay between the Laplace and hydrostatic pressure and from this description the capillary length is obtained. For different statepoints approaching the critical point the capillary length varies from 50 to 5 microm. These results are compared to theory. The mass density difference Deltarho is calculated from the bulk phase behavior, which is described within free volume theory with polymers modeled as penetrable hard spheres. The interfacial tension gamma is calculated within a squared gradient approximation. The capillary length is then given through with g equal to the Earth's acceleration. Predictions from theory are in overall qualitative agreement with experiment without the use of any adjustable parameter.
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Affiliation(s)
- D G A L Aarts
- Van't Hoff Laboratory, Debye Research Institute, University of Utrecht, Padualaan 8, 3584 CH Utrecht The Netherlands.
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