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Shandiz SA, Leuty GM, Guo H, Mokarizadeh AH, Maia JM, Tsige M. Structure and Thermodynamics of Linear, Ring, and Catenane Polymers in Solutions and at Liquid-Liquid Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:7154-7166. [PMID: 37155243 DOI: 10.1021/acs.langmuir.3c00589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
In recent decades, advances in the syntheses of mechanically interlocked macromolecules, such as catenanes, have led to much greater interest in the applications of these complexes, from molecular motors and actuators to nanoscale computational memory and nanoswitches. Much remains to be understood, however, regarding how catenated ring compounds behave as a result of the effects of different solvents as well as the effects of solvent/solvent interfaces. In this work, we have investigated, using molecular dynamics simulations, the effects of solvation of poly(ethylene oxide) chains of different topologies─linear, ring, and [2]catenane─in two solvents both considered favorable toward PEO (water, toluene) and at the water/toluene interface. Compared to ring and [2]catenane molecules, the linear PEO chain showed the largest increase in size at the water/toluene interface compared to bulk water or bulk toluene. Perhaps surprisingly, observations indicate that the tendency of all three topologies to extend at the water/toluene interface may have more to do with screening the interaction between the two solvents than with optimizing specific solvent-polymer contacts.
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Affiliation(s)
- Saeed Akbari Shandiz
- Department of Macromolecular Science & Engineering, Case Western Reserve University, Cleveland Ohio 44106, United States
| | - Gary M Leuty
- LinQuest Corporation, Beavercreek, Ohio 45431, United States
| | - Hao Guo
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Abdol Hadi Mokarizadeh
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Joao M Maia
- Department of Macromolecular Science & Engineering, Case Western Reserve University, Cleveland Ohio 44106, United States
| | - Mesfin Tsige
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, Ohio 44325, United States
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Nozawa T, Brumby PE, Ayuba S, Yasuoka K. Ordering in clusters of uniaxial anisotropic particles during homogeneous nucleation and growth. J Chem Phys 2019; 150:054903. [PMID: 30736692 DOI: 10.1063/1.5064410] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Takuma Nozawa
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Paul E. Brumby
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Sho Ayuba
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Kenji Yasuoka
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
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3
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DeBenedictis A, Atherton TJ, Rodarte AL, Hirst LS. Modeling deformation and chaining of flexible shells in a nematic solvent with finite elements on an adaptive moving mesh. Phys Rev E 2018; 97:032701. [PMID: 29776105 DOI: 10.1103/physreve.97.032701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Indexed: 06/08/2023]
Abstract
A micrometer-scale elastic shell immersed in a nematic liquid crystal may be deformed by the host if the cost of deformation is comparable to the cost of elastic deformation of the nematic. Moreover, such inclusions interact and form chains due to quadrupolar distortions induced in the host. A continuum theory model using finite elements is developed for this system, using mesh regularization and dynamic refinement to ensure quality of the numerical representation even for large deformations. From this model, we determine the influence of the shell elasticity, nematic elasticity, and anchoring condition on the shape of the shell and hence extract parameter values from an experimental realization. Extending the model to multibody interactions, we predict the alignment angle of the chain with respect to the host nematic as a function of aspect ratio, which is found to be in excellent agreement with experiments.
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Affiliation(s)
- Andrew DeBenedictis
- Department of Physics and Astronomy, Tufts University, 574 Boston Avenue, Medford, Massachusetts 02155, USA
| | - Timothy J Atherton
- Department of Physics and Astronomy, Tufts University, 574 Boston Avenue, Medford, Massachusetts 02155, USA
| | - Andrea L Rodarte
- Department of Physics, University of California, Merced, 5200 Lake Road, Merced, California 95343, USA
| | - Linda S Hirst
- Department of Physics, University of California, Merced, 5200 Lake Road, Merced, California 95343, USA
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Rull LF, Romero-Enrique JM. Nanodrops of Discotic Liquid Crystals: A Monte Carlo Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:11779-11787. [PMID: 28899095 DOI: 10.1021/acs.langmuir.7b02347] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We study the morphologies of nematic nanodrops in a vapor of a discotic nematogen by Monte Carlo simulations. The fluid interactions are modeled by a Gay-Berne model with molecular elongations of κ = 0.3 and 0.5 and different values of the energy anisotropy parameter κ' in the range of temperature T in which the nematic coexists with a vapor phase. We considered nanodrops of N = 4000 and 32 000 particles. For κ > κ', we observe that nanodrops are quite spherical (even for N = 4000 nanodrops), with a homogeneous director field for κ = 0.3 and a bipolar nematic configuration with tangential anchoring for κ = 0.5. By increasing the value of κ', nanodrops change from spherical to lens-shaped for κ = 0.3, and for κ = 0.5, spherical nanodrops with homeotropic anchoring and a disclination ring located on its equatorial plane are observed. Although no radial nanodrops are observed, isotropic liquid nanodrops with a paranematic shell and radial texture are observed for temperatures slightly above the vapor-isotropic-nematic triple point when the vapor-isotropic interface is completely wet by the nematic phase.
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Affiliation(s)
- Luis F Rull
- Departamento de Fı́sica Atómica, Molecular y Nuclear, Área de Fı́sica Teórica, Universidad de Sevilla , Avenida de Reina Mercedes s/n, 41012 Sevilla, Spain
| | - José M Romero-Enrique
- Departamento de Fı́sica Atómica, Molecular y Nuclear, Área de Fı́sica Teórica, Universidad de Sevilla , Avenida de Reina Mercedes s/n, 41012 Sevilla, Spain
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Rull LF, Romero-Enrique JM, Fernandez-Nieves A. Computer simulations of nematic drops: coupling between drop shape and nematic order. J Chem Phys 2012; 137:034505. [PMID: 22830709 DOI: 10.1063/1.4733974] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We perform Monte Carlo computer simulations of nematic drops in equilibrium with their vapor using a Gay-Berne interaction between the rod-like molecules. To generate the drops, we initially perform NPT simulations close to the nematic-vapor coexistence region, allow the system to equilibrate and subsequently induce a sudden volume expansion, followed with NVT simulations. The resultant drops coexist with their vapor and are generally not spherical but elongated, have the rod-like particles tangentially aligned at the surface and an overall nematic orientation along the main axis of the drop. We find that the drop eccentricity increases with increasing molecular elongation, κ. For small κ the nematic texture in the drop is bipolar with two surface defects, or boojums, maximizing their distance along this same axis. For sufficiently high κ, the shape of the drop becomes singular in the vicinity of the defects, and there is a crossover to an almost homogeneous texture; this reflects a transition from a spheroidal to a spindle-like drop.
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Affiliation(s)
- L F Rull
- Departamento de Física Atómica, Molecular y Nuclear, Área de Física Teórica, Universidad de Sevilla, Apartado de Correos 1065, 41080 Sevilla, Spain
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Gwizdała W, Górny K, Gburski Z. The dynamics of 4-cyano-4-n-pentylbiphenyl (5CB) mesogen molecules located between graphene layers--MD study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 79:701-704. [PMID: 20863751 DOI: 10.1016/j.saa.2010.08.040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 03/31/2010] [Accepted: 08/26/2010] [Indexed: 05/29/2023]
Abstract
The ultrathin film of mesogenic molecules 5CB confined between graphene walls has been investigated by molecular dynamics (MD) technique. The dynamical observables of 4-cyano-4-n-pentylbiphenyl (5CB) were calculated for several temperatures: the mean square displacement, translational and angular velocity autocorrelation function, and second-rank order parameter.
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Affiliation(s)
- W Gwizdała
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland.
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Janoschek F, Mancini F, Harting J, Toschi F. Rotational behaviour of red blood cells in suspension: a mesoscale simulation study. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:2337-2344. [PMID: 21536581 DOI: 10.1098/rsta.2011.0086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The nature of blood as a suspension of red blood cells makes computational haemodynamics a demanding task. Our coarse-grained blood model, which builds on a lattice Boltzmann method for soft particle suspensions, enables the study of the collective behaviour of the order of 10(6) cells in suspension. After demonstrating the viscosity measurement in Kolmogorov flow, we focus on the statistical analysis of the cell orientation and rotation in Couette flow. We quantify the average inclination with respect to the flow and the nematic order as a function of shear rate and haematocrit. We further record the distribution of rotation periods around the vorticity direction and find a pronounced peak in the vicinity of the theoretical value for free model cells, even though cell-cell interactions manifest themselves in a substantial width of the distribution.
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Affiliation(s)
- F Janoschek
- Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
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Bacchiocchi C, Miglioli I, Arcioni A, Vecchi I, Rai K, Fontecchio A, Zannoni C. Order and Dynamics Inside H-PDLC Nanodroplets: An ESR Spin Probe Study. J Phys Chem B 2009; 113:5391-402. [DOI: 10.1021/jp8105887] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Corrado Bacchiocchi
- Dipartimento di Chimica Fisica e Inorganica and INSTM, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy, and Department of Electrical and Computer Engineering, Drexel University, Philadelphia, Pennsylvania 19104
| | - Isabella Miglioli
- Dipartimento di Chimica Fisica e Inorganica and INSTM, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy, and Department of Electrical and Computer Engineering, Drexel University, Philadelphia, Pennsylvania 19104
| | - Alberto Arcioni
- Dipartimento di Chimica Fisica e Inorganica and INSTM, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy, and Department of Electrical and Computer Engineering, Drexel University, Philadelphia, Pennsylvania 19104
| | - Ilaria Vecchi
- Dipartimento di Chimica Fisica e Inorganica and INSTM, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy, and Department of Electrical and Computer Engineering, Drexel University, Philadelphia, Pennsylvania 19104
| | - Kashma Rai
- Dipartimento di Chimica Fisica e Inorganica and INSTM, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy, and Department of Electrical and Computer Engineering, Drexel University, Philadelphia, Pennsylvania 19104
| | - Adam Fontecchio
- Dipartimento di Chimica Fisica e Inorganica and INSTM, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy, and Department of Electrical and Computer Engineering, Drexel University, Philadelphia, Pennsylvania 19104
| | - Claudio Zannoni
- Dipartimento di Chimica Fisica e Inorganica and INSTM, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy, and Department of Electrical and Computer Engineering, Drexel University, Philadelphia, Pennsylvania 19104
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Karayiannis NC, Laso M, Kröger M. Detailed Atomistic Molecular Dynamics Simulations of α-Conotoxin AuIB in Water. J Phys Chem B 2009; 113:5016-24. [DOI: 10.1021/jp806734c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Nikos Ch. Karayiannis
- Institute for Optoelectronics and Microsystems (ISOM) and ETSII, Universidad Politécnica de Madrid (UPM), José Gutiérrez Abascal 2, E-28006 Madrid, Spain
| | - Manuel Laso
- Institute for Optoelectronics and Microsystems (ISOM) and ETSII, Universidad Politécnica de Madrid (UPM), José Gutiérrez Abascal 2, E-28006 Madrid, Spain
| | - Martin Kröger
- Polymer Physics, ETH Zürich, Department of Materials, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
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Berardi R, Costantini A, Muccioli L, Orlandi S, Zannoni C. A computer simulation study of the formation of liquid crystal nanodroplets from a homogeneous solution. J Chem Phys 2007; 126:044905. [PMID: 17286507 DOI: 10.1063/1.2430710] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The aggregation of liquid crystal nanodroplets from a homogeneous solution is an important but not well understood step in the preparation of various advanced photonic materials. Here, the authors performed molecular dynamics computer simulations of the formation of liquid crystalline nanodroplets, starting from an isotropic and uniform binary solution of spherical Lennard-Jones (solvent) and elongated ellipsoidal Gay-Berne (solute) rigid particles in low (<10%) concentration. They studied the dynamics of demixing and the mesogen ordering process and characterized the resulting nanodroplets assessing the effect of temperature, composition, and specific solute-solvent interaction on the morphology, structure, and anisotropy. They find that the specific solute-solvent interaction, composition, and temperature can be adjusted to tune the nanodroplet growth and size.
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Affiliation(s)
- Roberto Berardi
- Dipartimento di Chimica Fisica e Inorganica, Università di Bologna, Viale Risorgimento 4, 40136 Bologna, Italy
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12
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Lupo JA, Wang Z, McKenney AM, Pachter R, Mattson W. A large scale molecular dynamics simulation code using the fast multipole algorithm (FMD): performance and application. J Mol Graph Model 2002; 21:89-99. [PMID: 12398340 DOI: 10.1016/s1093-3263(02)00125-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We present the performance of the fast classical molecular dynamics (MD) code, fast molecular dynamics (FMD), designed for efficient, object-oriented, and scalable large scale simulations, and summarize its application to a liquid crystalline cluster. FMD uses an implementation of the three-dimensional fast multipole method, developed in our group. The fast multipole method offers an efficient way (order O(N)) to handle long range electrostatic interactions, thus, enabling more realistic simulations of large molecular systems. Performance testing was carried out on IBM SP2, SGI Origin 2000, and CRAY T3E massively parallel systems using the MPI massage passing library. The electrostatic forces were tested on models of up to 100,000 randomly placed charges, and on protein and liquid crystalline molecular systems of over 99,000 atoms. Tests on the stability of the method are presented, along with comparisons with direct calculations, the NAMD2 code, and the physical multipole-based cell-multipole method.
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Affiliation(s)
- James A Lupo
- Materials Directorate, Air Force Research Laboratory, Wright-Patterson, AFB, OH 45433-7702, USA
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Tsige M, Taylor PL. Simulation study of the glass transition temperature in poly(methyl methacrylate). PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2002; 65:021805. [PMID: 11863553 DOI: 10.1103/physreve.65.021805] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2001] [Indexed: 05/23/2023]
Abstract
The glass transition in syndiotactic poly (methyl methacrylate) has been studied through atomistic molecular dynamics simulations performed at temperatures in the range from 297 K to 684 K. The mean squared deviations of atoms, monomers, and molecules from their initial positions were analyzed by means of a technique that separates the effects of diffusive motion from the underlying vibrational motion. The diffusive motion shows a novel power-law variation with time, with an exponent that varies continuously from 0.5 below the glass transition temperature T(g) to 1 at high temperatures. The self part of the van Hove correlation functions for both hydrogen atoms and monomers shows structural arrest at the lowest temperature studied. A second peak in the atomic van Hove correlation is attributed to rotation of the CH3 group.
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Affiliation(s)
- Mesfin Tsige
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106-7079, USA
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Wang Z, Lupo JA, Patnaik S, Pachter R. Large scale molecular dynamics simulations of a 4-n-pentyl-4′-cyanobiphenyl (5CB) liquid crystalline model in the bulk and as a droplet. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s1089-3156(01)00017-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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