1
|
Tani A, Tanii Y, Ishiyama K, Harada S, Satoh H. Structural transition of various-sized sphere-platelet mixtures. Phys Rev E 2022; 105:044602. [PMID: 35590607 DOI: 10.1103/physreve.105.044602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 03/15/2022] [Indexed: 06/15/2023]
Abstract
Monte Carlo simulations on the structural change of hard sphere-platelet mixtures were performed to investigate the effect of particle size. We quantitatively analyzed local equilibrium structures of sphere-platelet mixtures with varying size ratios under various sphere and platelet density conditions. Based on the simulation results, we investigated the structural transitions such as isotropic to anisotropic, clustering, and so on. When a small amount of small-sized sphere is added to a large-sized platelet system, the mixture structure transitions from isotropic to nematic ones as the platelet number density increases. On the other hand, the platelet forms clusters with the addition of a large number of spheres. In a small platelet-large sphere system, the spheres form aggregates by increasing platelet density instead. The platelet and spherical particles exhibit different structural transitions depending on the size and density. In the limit of small and large size ratios, the structures of the platelet-sphere mixture obtained from the Monte Carlo simulation are close to those shown by previous theoretical and experimental studies, respectively. Because the primary actor shifts from sphere to platelet as the size ratio changes, the transition boundary shifts continuously. When the size ratio is close to unity, the most complicated behavior is observed, with both the platelet and sphere simultaneously acting the leading part.
Collapse
Affiliation(s)
- Akiho Tani
- Faculty of Engineering, Hokkaido University, N13-W8 Sapporo, Hokkaido 060-8628, Japan
| | - Yutaro Tanii
- Faculty of Engineering, Hokkaido University, N13-W8 Sapporo, Hokkaido 060-8628, Japan
| | - Kyoka Ishiyama
- Faculty of Engineering, Hokkaido University, N13-W8 Sapporo, Hokkaido 060-8628, Japan
| | - Shusaku Harada
- Faculty of Engineering, Hokkaido University, N13-W8 Sapporo, Hokkaido 060-8628, Japan
| | - Hisao Satoh
- Japan Nuclear Fuel Limited, 504-22 Nozuki, Obuchi, Rokkasho, Aomori 039-3212, Japan
| |
Collapse
|
2
|
Mizani S, Aliabadi R, Salehi H, Varga S. Orientational ordering and layering of hard plates in narrow slitlike pores. Phys Rev E 2019; 100:032704. [PMID: 31639981 DOI: 10.1103/physreve.100.032704] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Indexed: 11/07/2022]
Abstract
We examine the ordering behavior of hard platelike particles in a very narrow, slitlike pore using the Parsons-Lee density functional theory and the restricted orientation approximation. We observe that the plates are orientationally ordered and align perpendicularly (face-on) to the walls at low densities, a first-order layering transition occurs between uniaxial nematic structures having n and n+1 layers at intermediate densities, and even a phase transition between a monolayer with parallel (edge-on) orientational order and n layers with a perpendicular one can be detected at high densities. In addition to this, the edge-on monolayer is usually biaxial nematic, and a uniaxial-biaxial nematic phase transition can be also seen at very high densities.
Collapse
Affiliation(s)
- Sakine Mizani
- Department of Physics, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Roohollah Aliabadi
- Department of Physics, Faculty of Science, Fasa University, 74617-81189 Fasa, Iran
| | - Hamdollah Salehi
- Department of Physics, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Szabolcs Varga
- Institute of Physics and Mechatronics, University of Pannonia, P.O. Box 158, Veszprém H-8201, Hungary
| |
Collapse
|
3
|
González-Martínez AD, Chávez-Rojo MA, Sambriski EJ, Moreno-Razo JA. Defect-mediated colloidal interactions in a nematic-phase discotic solvent. RSC Adv 2019; 9:33413-33427. [PMID: 35529161 PMCID: PMC9073280 DOI: 10.1039/c9ra05377h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 09/04/2019] [Indexed: 01/30/2023] Open
Abstract
Interactions between colloidal inclusions dispersed in a nematic discotic liquid-crystalline solvent were investigated for different solute-solvent coupling conditions. The solvent was treated at the level of Gay-Berne discogens. Colloidal inclusions were coupled to the solvent with a generalized sphere-ellipsoid interaction potential. Energy strengths were varied to promote either homeotropic or planar mesogenic anchoring. Colloid-colloid interactions were modeled using a soft, excluded-volume contribution. Single-colloid and colloid-pair samples were evolved with Molecular Dynamics simulations. Equilibrium trajectories were used to characterize structural and dynamical properties of topological defects arising in the mesomorphic phase due to colloidal inclusions. Boojums were observed with planar anchoring, whereas Saturn rings were obtained with homeotropic anchoring. The manner in which these topological defects drive colloidal interactions was assessed through a free energy analysis, taking into account the relative orientation between a colloidal dyad and the nematic-field director. The dynamical behavior of defects was qualitatively surveyed from equilibrium trajectories borne from computer simulations.
Collapse
Affiliation(s)
- Aurora D González-Martínez
- Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa Avenida San Rafael Atlixco No. 186, Colonia Vicentina, Delegación Iztapalapa Mexico City 09340 Mexico
| | - Marco A Chávez-Rojo
- Facultad de Ciencias Químicas, Universidad Autónoma de Chihuahua Circuito Universitario #1 s/n, Nuevo Campus Universitario Chihuahua Chihuahua 31000 Mexico
| | - Edward J Sambriski
- Department of Chemistry, Delaware Valley University Doylestown Pennsylvania 18901 USA
| | - José A Moreno-Razo
- Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa Avenida San Rafael Atlixco No. 186, Colonia Vicentina, Delegación Iztapalapa Mexico City 09340 Mexico
| |
Collapse
|
4
|
García ÁG, Tuinier R, Maring JV, Opdam J, Wensink HH, Lekkerkerker HNW. Depletion-driven four-phase coexistences in discotic systems. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1463471] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Álvaro González García
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, & Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology , Eindhoven, The Netherlands
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Department of Chemistry & Debye Institute, Utrecht University , Utrecht, The Netherlands
| | - Remco Tuinier
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, & Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology , Eindhoven, The Netherlands
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Department of Chemistry & Debye Institute, Utrecht University , Utrecht, The Netherlands
| | - Jasper V. Maring
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, & Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology , Eindhoven, The Netherlands
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Department of Chemistry & Debye Institute, Utrecht University , Utrecht, The Netherlands
| | - Joeri Opdam
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, & Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology , Eindhoven, The Netherlands
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Department of Chemistry & Debye Institute, Utrecht University , Utrecht, The Netherlands
| | - Henricus H. Wensink
- Laboratoire de Physique des Solides - UMR 8502, Université Paris-Sud, Université Paris-Saclay and CNRS , Orsay, France
| | - Henk N. W. Lekkerkerker
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Department of Chemistry & Debye Institute, Utrecht University , Utrecht, The Netherlands
| |
Collapse
|
5
|
Abstract
Stability is of paramount importance in colloidal applications. Attraction between colloidal particles is believed to lead to particle aggregation and phase separation; hence, stability improvement can be achieved through either increasing repulsion or reducing attraction by modifying the fluid medium or by using additives. Two traditional mechanisms for colloidal stability are electrostatic stabilization and steric stabilization. However, stability improvement by mixing attractive and unstable particles has rarely been considered. Here, we emphasize the function of mixing entropy in colloidal stabilization. Dispersion stability improvement is demonstrated by mixing suspensions of attractive nanosized titania spheres and platelets. A three-dimensional phase diagram is proposed to illustrate the collaborative effects of particle mixing and particle attraction on colloidal stability. This discovery provides a novel method for enhancing colloidal stability and opens a novel opportunity for engineering applications.
Collapse
|
6
|
Gratale MD, Still T, Matyas C, Davidson ZS, Lobel S, Collings PJ, Yodh AG. Tunable depletion potentials driven by shape variation of surfactant micelles. Phys Rev E 2016; 93:050601. [PMID: 27300818 DOI: 10.1103/physreve.93.050601] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Indexed: 06/06/2023]
Abstract
Depletion interaction potentials between micron-sized colloidal particles are induced by nanometer-scale surfactant micelles composed of hexaethylene glycol monododecyl ether (C_{12}E_{6}), and they are measured by video microscopy. The strength and range of the depletion interaction is revealed to arise from variations in shape anisotropy of the surfactant micelles. This shape anisotropy increases with increasing sample temperature. By fitting the colloidal interaction potentials to theoretical models, we extract micelle length and shape anisotropy as a function of temperature. This work introduces shape anisotropy tuning as a means to control interparticle interactions in colloidal suspensions, and it shows how the interparticle depletion potentials of micron-scale objects can be employed to probe the shape and size of surrounding macromolecules at the nanoscale.
Collapse
Affiliation(s)
- Matthew D Gratale
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Tim Still
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Caitlin Matyas
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- The Arts Academy at Benjamin Rush, Philadelphia, Pennsylvania 19154, USA
| | - Zoey S Davidson
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Samuel Lobel
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Peter J Collings
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Physics and Astronomy, Swarthmore College, Swarthmore, Pennsylvania 19081, USA
| | - A G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| |
Collapse
|
7
|
Aliabadi R, Moradi M, Varga S. Tracking three-phase coexistences in binary mixtures of hard plates and spheres. J Chem Phys 2016; 144:074902. [DOI: 10.1063/1.4941981] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
8
|
Lekkerkerker H, Tuinier R, Wensink H. Multiphase coexistence in mixed suspensions of large and small hard platelets. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1048319] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- H.N.W. Lekkerkerker
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University , Utrecht, the Netherlands
| | - R. Tuinier
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry and Institute for Complex Molecular Systems, Eindhoven University of Technology , Eindhoven, the Netherlands
| | - H.H. Wensink
- Laboratoire de Physique des Solides, Université Paris-Sud and CNRS , Orsay Cedex, France
| |
Collapse
|
9
|
|
10
|
Gámez F, Acemel RD, Cuetos A. Demixing and nematic behaviour of oblate hard spherocylinders and hard spheres mixtures: Monte Carlo simulation and Parsons–Lee theory. Mol Phys 2013. [DOI: 10.1080/00268976.2013.771802] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
11
|
de las Heras D, Schmidt M. Bulk fluid phase behaviour of colloidal platelet-sphere and platelet-polymer mixtures. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2013; 371:20120259. [PMID: 23459962 DOI: 10.1098/rsta.2012.0259] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Using a geometry-based fundamental measure density functional theory, we calculate bulk fluid phase diagrams of colloidal mixtures of vanishingly thin hard circular platelets and hard spheres. We find isotropic-nematic phase separation, with strong broadening of the biphasic region, upon increasing the pressure. In mixtures with large size ratio of platelet and sphere diameters, there is also demixing between two nematic phases with differing platelet concentrations. We formulate a fundamental measure density functional for mixtures of colloidal platelets and freely overlapping spheres, which represent ideal polymers, and use it to obtain phase diagrams. We find that, for low platelet-polymer size ratio, in addition to isotropic-nematic and nematic-nematic phase coexistence, platelet-polymer mixtures also display isotropic-isotropic demixing. By contrast, we do not find isotropic-isotropic demixing in hard-core platelet-sphere mixtures for the size ratios considered.
Collapse
Affiliation(s)
- Daniel de las Heras
- Theoretische Physik II, Physikalisches Institut, Universität Bayreuth, 95440 Bayreuth, Germany.
| | | |
Collapse
|
12
|
Cinacchi G, Doshi N, Prescott SW, Cosgrove T, Grillo I, Lindner P, Phipps JS, Gittins D, van Duijneveldt JS. The effect of size ratio on the sphere structure factor in colloidal sphere-plate mixtures. J Chem Phys 2012. [DOI: 10.1063/1.4767722] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
|
13
|
Floating nematic phase in colloidal platelet-sphere mixtures. Sci Rep 2012; 2:789. [PMID: 23145313 PMCID: PMC3494036 DOI: 10.1038/srep00789] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 10/09/2012] [Indexed: 11/08/2022] Open
Abstract
The phase behaviour of colloidal dispersions is interesting for fundamental reasons and for technological applications such as photonic crystals and electronic paper. Sedimentation, which in everyday life is relevant from blood analysis to the shelf life of paint, is a means to determine phase boundaries by observing distinct layers in samples that are in sedimentation-diffusion equilibrium. However, disentangling the effects due to interparticle interactions, which generate the bulk phase diagram, from those due to gravity is a complex task. Here we show that a line in the space of chemical potentials µ(i), where i labels the species, represents a sedimented sample and that each crossing of this sedimentation path with a binodal generates an interface under gravity. Complex phase stacks can result, such as the sandwich of a floating nematic layer between top and bottom isotropic phases that we observed in a mixture of silica spheres and gibbsite platelets.
Collapse
|
14
|
|