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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.
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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
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Mazzilli V, Satoh K, Saielli G. Mixtures of discotic and spherical soft particles: de-mixing, liquid crystal behaviour and relative solubility. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.117973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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3
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Behzadi F, Ghazi SM, Aliabadi R. From n-layer planar ordering to the monolayer homeotropic structure of confined hard rods: The effect of shape anisotropy and wall-to-wall separation. Phys Rev E 2021; 103:022702. [PMID: 33735962 DOI: 10.1103/physreve.103.022702] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 01/13/2021] [Indexed: 11/07/2022]
Abstract
Using the Parsons-Lee theory, we examined the effect of shape anisotropy and the wall-to-wall separation (H) on the phase behavior of the hard parallelepiped rods with dimensions L, D, and D (L>D) in such narrow slitlike pores which only one homeotropic layer can form. The phase structures, including biaxiality, planar nematic layering transition as well as planar to homeotropic, were studied for some separations in the range 2.5D≤H≤10.0D for H-D≤L<H.
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Affiliation(s)
- Fahimeh Behzadi
- Department of Physics, Faculty of Science, Fasa University, 74617-81189 Fasa, Iran
| | - Seyed Mohammad Ghazi
- Department of Physics, Faculty of Science, Fasa University, 74617-81189 Fasa, Iran
| | - Roohollah Aliabadi
- Department of Physics, Faculty of Science, Fasa University, 74617-81189 Fasa, Iran
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González García Á, Tuinier R, de With G, Cuetos A. Directional-dependent pockets drive columnar-columnar coexistence. SOFT MATTER 2020; 16:6720-6724. [PMID: 32578661 DOI: 10.1039/d0sm00802h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The rational design of materials requires a fundamental understanding of the mechanisms driving their self-assembly. This may be particularly challenging in highly dense and shape-asymmetric systems. Here we show how the addition of tiny non-adsorbing spheres (depletants) to a dense system of hard disc-like particles (discotics) leads to coexistence between two distinct, highly dense (liquid)-crystalline columnar phases. This coexistence emerges due to the directional-dependent free-volume pockets for depletants. Theoretical results are confirmed by simulations explicitly accounting for the binary mixture of interest. We define the stability limits of this columnar-columnar coexistence and quantify the directional-dependent depletant partitioning.
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Affiliation(s)
- Álvaro González García
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, The Netherlands. and Van't Hoff Laboratory for Physical and Colloid Chemistry, Department of Chemistry & Debye Institute, Utrecht University, The Netherlands.
| | - Remco Tuinier
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Department of Chemistry & Debye Institute, Utrecht University, The Netherlands.
| | - Gijsbertus de With
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Department of Chemistry & Debye Institute, Utrecht University, The Netherlands.
| | - Alejandro Cuetos
- Department of Physical, Chemical and Natural Systems, Universidad Pablo Olavide, 41013 Sevilla, Spain
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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.
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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
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6
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Affiliation(s)
- Michael P. Allen
- Department of Physics, University of Warwick, Coventry, UK
- H. H. Wills Physics Laboratory, Royal Fort, Bristol, UK
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Hvozd M, Patsahan T, Holovko M. Isotropic-Nematic Transition and Demixing Behavior in Binary Mixtures of Hard Spheres and Hard Spherocylinders Confined in a Disordered Porous Medium: Scaled Particle Theory. J Phys Chem B 2018; 122:5534-5546. [PMID: 29385800 DOI: 10.1021/acs.jpcb.7b11834] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We develop the scaled particle theory to describe the thermodynamic properties and orientation ordering of a binary mixture of hard spheres (HS) and hard spherocylinders (HSC) confined in a disordered porous medium. Using this theory, the analytical expressions of the free energy, the pressure, and the chemical potentials of HS and HSC have been derived. The improvement of obtained results is considered by introducing the Carnahan-Starling-like and Parsons-Lee-like corrections. Phase diagrams for the isotropic-nematic transition are calculated from the bifurcation analysis of the integral equation for the orientation singlet distribution function and from the conditions of thermodynamic equilibrium. Both the approaches correctly predict the isotropic-nematic transition at low concentrations of hard spheres. However, the thermodynamic approach provides more accurate results and is able to describe the demixing phenomena in the isotropic and nematic phases. The effects of porous medium on the isotropic-nematic phase transition and demixing behavior in a binary HS/HSC mixture are discussed.
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Affiliation(s)
- M Hvozd
- Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine , 1 Svientsitskii Street , 79011 Lviv , Ukraine
| | - T Patsahan
- Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine , 1 Svientsitskii Street , 79011 Lviv , Ukraine
| | - M Holovko
- Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine , 1 Svientsitskii Street , 79011 Lviv , Ukraine
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Wu L, Malijevský A, Avendaño C, Müller EA, Jackson G. Demixing, surface nematization, and competing adsorption in binary mixtures of hard rods and hard spheres under confinement. J Chem Phys 2018; 148:164701. [DOI: 10.1063/1.5020002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Liang Wu
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Alexandr Malijevský
- Department of Physical Chemistry, University of Chemical Technology Prague, 166 28 Praha 6, Czech Republic
- Department of Microscopic and Mesoscopic Modelling, ICPF of the Czech Academy of Sciences, 165 02 Prague 6, Czech Republic
| | - Carlos Avendaño
- School of Chemical Engineering and Analytical Science, The University of Manchester, Sackville Street, Manchester M13 9PL, United Kingdom
| | - Erich A. Müller
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - George Jackson
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
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Zhao H, An X, Qian Q, Wu Y, Wang L, Li W, Yang X. Experimental study on the packing densification of mixtures of spherical and cylindrical particles subjected to 3D vibrations. PARTICULATE SCIENCE AND TECHNOLOGY 2018. [DOI: 10.1080/02726351.2017.1373378] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Haiyang Zhao
- School of Metallurgy, Northeastern University, Shenyang, P.R. China
| | - Xizhong An
- School of Metallurgy, Northeastern University, Shenyang, P.R. China
| | - Quan Qian
- School of Metallurgy, Northeastern University, Shenyang, P.R. China
| | - Yongli Wu
- Department of Chemical Engineering, Monash University, Clayton, VIC, Australia
| | - Lin Wang
- School of Metallurgy, Northeastern University, Shenyang, P.R. China
| | - Wufa Li
- School of Metallurgy, Northeastern University, Shenyang, P.R. China
| | - Xiaohong Yang
- School of Metallurgy, Northeastern University, Shenyang, P.R. China
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Chen M, He M, Lin P, Chen Y, Cheng Z. Staged phase separation in the I-I-N tri-phase region of platelet-sphere mixtures. SOFT MATTER 2017; 13:4457-4463. [PMID: 28580472 DOI: 10.1039/c7sm00478h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Mixtures of colloids with different sizes or shapes are ubiquitous in nature and extensively applied in industries. Phase transition pathways and kinetics in this model system should be investigated because of the difficulty in observing tri-phase coexistence in colloidal platelet-sphere mixtures. Similar to the polymer-sphere mixtures, the phase transition pathway has three main categories. Analytical results show a staged phase transition process in which the mixture first separates into one or two metastable phases, then further separates, and subsequently reaches tri-phase equilibrium. Unique to our system, and different from the gas-liquid-crystal coexistence in colloid-polymer mixtures, the platelet-sphere mixture reached a gas-liquid-liquid crystal (nematic) coexistence. Thus, the different phases are easy to distinguish using the birefringence of the liquid crystals. In addition, the volume fraction of the liquid crystal formation in the ZrP platelet suspensions is much lower than for the crystal formation in hard spheres.
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Affiliation(s)
- Mingfeng Chen
- Soft Matter Center, Guangdong Provincial Key Laboratory on Functional Soft Condensed Matter, School of Materials and Energy, Guangdong University of Technology, Guangzhou, 510006, China
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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
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Cienega-Cacerez O, García-Alcántara C, Moreno-Razo JA, Díaz-Herrera E, Sambriski EJ. Induced stabilization of columnar phases in binary mixtures of discotic liquid crystals. SOFT MATTER 2016; 12:1295-1312. [PMID: 26576703 DOI: 10.1039/c5sm01959a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Three discotic liquid-crystalline binary mixtures, characterized by their extent of bidispersity in molecular thickness, were investigated with molecular dynamics simulations. Each equimolar mixture contained A-type (thin) and B-type (thick) discogens. The temperature-dependence of the orientational order parameter reveals that A-type liquid samples produce ordered phases more readily, with the (hexagonal) columnar phase being the most structured variant. Moderately and strongly bidisperse mixtures produce globally-segregated samples for temperatures corresponding to ordered phases; the weakly bidisperse mixture displays microheterogeneities. Ordered phases in the B-type liquid are induced partially by the presence of the A-type fluid. In the moderately bidisperse mixture, order is induced through orientational frustration: a mixed prenematic-like phase precedes global segregation to yield nematic and columnar mesophases upon further cooling. In the strongly bidisperse mixture, order is induced less efficiently through a paranematic-like mechanism: a highly-ordered A-type fluid imparts order to B-type discogens found at the interface of a fully-segregated sample. This ordering effect permeates into the disordered B-type domain until nematic and columnar phases emerge upon further cooling. At sufficiently low temperatures, all samples investigated exhibit the (hexagonal) columnar mesophase.
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Affiliation(s)
- Octavio Cienega-Cacerez
- Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, Avenida San Rafael Atlixco No. 186, Colonia Vicentina, Delegación Iztapalapa, México, D.F. 09340, Mexico
| | - Consuelo García-Alcántara
- Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, Avenida San Rafael Atlixco No. 186, Colonia Vicentina, Delegación Iztapalapa, México, D.F. 09340, Mexico and Unidad Multidisciplinaria de Docencia e Investigación-Juriquilla, Facultad de Ciencias, Universidad Nacional Autónoma de México, Campus Juriquilla, Boulevard Juriquilla 3001, Juriquilla, Querétaro 76230, Mexico
| | - José Antonio Moreno-Razo
- Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, Avenida San Rafael Atlixco No. 186, Colonia Vicentina, Delegación Iztapalapa, México, D.F. 09340, Mexico
| | - Enrique Díaz-Herrera
- Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, Avenida San Rafael Atlixco No. 186, Colonia Vicentina, Delegación Iztapalapa, México, D.F. 09340, Mexico
| | - Edward John Sambriski
- Department of Chemistry, Delaware Valley University, 700 East Butler Avenue, Doylestown, Pennsylvania 18901, USA.
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Piedrahita M, Cuetos A, Martínez-Haya B. Transport of spherical colloids in layered phases of binary mixtures with rod-like particles. SOFT MATTER 2015; 11:3432-3440. [PMID: 25797280 DOI: 10.1039/c4sm02865a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The transport properties of colloids in anisotropic media constitute a general problem of fundamental interest in experimental sciences, with a broad range of technological applications. This work investigates the transport of soft spherical colloids in binary mixtures with rod-like particles by means of Monte Carlo and Brownian Dynamics simulations. Layered phases are considered, that range from smectic phases to lamellar phases, depending on the molar fraction of the spherical particles. The investigation serves to characterize the distinct features of transport within layers versus those of transport across neighboring layers, both of which are neatly differentiated. The insertion of particles into layers and the diffusion across them occur at a smaller rate than the intralayer diffusion modulated by the formation of transitory cages in its initial stages. Collective events, in which two or more colloids diffuse across layers in a concerted way, are described as a non-negligible process in these fluids.
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Affiliation(s)
- Mauricio Piedrahita
- Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville, Spain.
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