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Pal S, Chakrabarti J, Chakrabarty S. Anisotropic remixing of a phase separated binary colloidal system with particles of different sizes in an external modulation. J Chem Phys 2024; 160:214902. [PMID: 38836457 DOI: 10.1063/5.0190299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 05/21/2024] [Indexed: 06/06/2024] Open
Abstract
We explore the phase behavior of a binary colloidal system under external spatially periodic modulation. We perform Monte Carlo simulations on a binary mixture of big and small repulsive Lennard-Jones particles with a diameter ratio of 2:1. We characterize structure by isotropic and anisotropic pair correlation functions, cluster size distribution, bond angle distribution, order parameter, and specific heat. We observe the demixing of the species in the absence of external modulation. However, the mixing of the species gets enhanced with increasing potential strength along with the alignment of the particles transverse to the modulation. The de-mixing order parameter shows discontinuity with increasing modulation strength, characterizing a first order phase transition. The peak in specific heat increases linearly with the size of the system. We also look into the dynamical behavior of the system via computing Mean Square Displacement (MSD) along both parallel and perpendicular directions to the modulation. We observe a decrease in the diffusion coefficient for both types of particles as we increase the strength of the modulation.
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Affiliation(s)
- Suravi Pal
- Department of Physics of Complex Systems, S. N. Bose National Centre for Basic Sciences, JD Block, Sector-III, Salt Lake, Kolkata 700106, India
| | - Jaydeb Chakrabarti
- Department of Physics of Complex Systems, S. N. Bose National Centre for Basic Sciences, JD Block, Sector-III, Salt Lake, Kolkata 700106, India
| | - Srabani Chakrabarty
- Department of Physics, Lady Brabourne College, P-1/2, Suhrawardy Ave., Kolkata 700017, India
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Yu H, Jack RL. Competition between lanes and transient jammed clusters in driven binary mixtures. Phys Rev E 2024; 109:024123. [PMID: 38491710 DOI: 10.1103/physreve.109.024123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 01/23/2024] [Indexed: 03/18/2024]
Abstract
We consider mixtures of oppositely driven particles, showing that their nonequilibrium steady states form lanes parallel to the drive, which coexist with transient jammed clusters where particles are temporarily immobilized. We analyze the interplay between these two types of nonequilibrium pattern formation, including their implications for macroscopic demixing perpendicular to the drive. Finite-size scaling analysis indicates that there is no critical driving force associated with demixing, which appears as a crossover in finite systems. We attribute this effect to the disruption of long-ranged order by the transient jammed clusters.
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Affiliation(s)
- Honghao Yu
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Robert L Jack
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom
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Karmakar R, Chakrabarti J. Hot crystals of thermo-responsive particles with temperature dependent diameter in the presence of a temperature gradient. J Chem Phys 2023; 159:034904. [PMID: 37466232 DOI: 10.1063/5.0157604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 06/29/2023] [Indexed: 07/20/2023] Open
Abstract
Structure formation under non-equilibrium steady state conditions is poorly understood. A non-equilibrium steady state can be achieved in a system by maintaining a temperature gradient. A class of cross-linked microgel particles, such as poly-N-iso-propylacrylamide, is reported to increase in size due to the adsorption of water as the temperature decreases. Here, we study thermo-responsive particles with a temperature sensitive diameter in the presence of a temperature gradient, using molecular dynamics simulations with the Langevin thermostat. We find long-ranged structural order using bond order parameters in both cold and hot regions of the system beyond a certain diameter ratio of the cold and hot particles. This is due to an increase in packing and pressure in both regions. Our observations might be useful in understanding ordered structures under extreme conditions of a non-equilibrium steady state.
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Affiliation(s)
- Rahul Karmakar
- Department of Physics of Complex Systems, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake Kolkata 700106, India
| | - J Chakrabarti
- Department of Physics of Complex Systems, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake Kolkata 700106, India
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Yu H, Thijssen K, Jack RL. Perpendicular and parallel phase separation in two-species driven diffusive lattice gases. Phys Rev E 2022; 106:024129. [PMID: 36110007 DOI: 10.1103/physreve.106.024129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/01/2022] [Indexed: 06/15/2023]
Abstract
We study three different lattice models in which two species of diffusing particles are driven in opposite directions by an electric field. We focus on dynamical phase transitions that involve phase separation into domains that may be parallel or perpendicular to a driving field. In all cases, the perpendicular state appears for weak driving, consistent with previous work. For strong driving, we introduce two models that support the parallel state. In one model, this state occurs because of the inclusion of dynamical rules that enhance lateral diffusion during collisions; in the other, it is a result of a nearest-neighbor attractive or repulsive interaction between particles of the same or opposite species. We discuss the connections between these results and the behavior found in off-lattice systems, including laning and freezing by heating.
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Affiliation(s)
- Honghao Yu
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Kristian Thijssen
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Robert L Jack
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom
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Wang Y, Ma R, Li H, Hu S, Gao Y, Liu L, Zhao X, Zhang L. Effect of the content and strength of hard segment on the viscoelasticity of the polyurethane elastomer: insights from molecular dynamics simulation. SOFT MATTER 2022; 18:4090-4101. [PMID: 35575258 DOI: 10.1039/d2sm00463a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Due to the wide application, it is very crucial to understand the viscoelasticity of the polyurethane elastomer (PU, denoted by soft-hard block copolymer), which contains the soft segments (SS) and hard segments (HS). Thus, in this work, the effect of the content and strength of HS on the viscoelasticity of PU is explored in detail by adopting a coarse-grained model. First, the phase morphology of PU is characterized where both the single continuous phase and the bicontinuous phase are observed by varying the content of HS. Then, the viscoelasticity of PU is calculated by analyzing the storage modulus, the loss modulus, and the loss factor, which depends on the content and strength of HS. To further elucidate the mechanism for the storage modulus, the normalized interaction energy, the order parameter, and the formation probability of the HS or SS phase are characterized with the shear strain amplitude, which reflects the deformation of the phase structure. Then, the energy dissipation is quantified, which can rationalize the loss modulus well. A parameter is introduced, which considers the relative slippage and the content of HS or SS. It can explain the change in the loss factor with the content and strength of HS. In summary, this work can help to further understand how the content and strength of hard segments affect the viscoelasticity of the soft-hard block PU and structure evolution at the molecular level.
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Affiliation(s)
- Yimin Wang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Ruibin Ma
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Haoxiang Li
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Shikai Hu
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Yangyang Gao
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Li Liu
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Xiuying Zhao
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Liqun Zhang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
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Karmakar R, Chakrabarti J. A long-range order in a thermally driven system with temperature-dependent interactions. SOFT MATTER 2022; 18:867-876. [PMID: 35001096 DOI: 10.1039/d1sm01379c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Aggregation of macro-molecules under an external force is far from being understood. An important driving situation is achieved by temperature difference. Inter-particle interactions in metallic nanoparticles with ligand capping are reported to be sensitive to temperature and the zeta potential of the particles being reduced in the cold region. Such particles form aggregates in the cold region of the system in the presence of temperature difference. Here we study the aggregation of particles in the presence of temperature difference with temperature-dependent interaction parameters using Brownian dynamics simulation. The particle interaction and particle diffusion are considered to be sensitive to the local temperature. We identify a long-range structural order in the cold region of the system using the Avrami equation for crystal growth kinetics. Our observations might be useful in designing ordered structures with macro-molecules under non-equilibrium steady-state conditions.
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Affiliation(s)
- Rahul Karmakar
- Department of Chemical, Biological and Macro-Molecular Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700106, India.
| | - J Chakrabarti
- Department of Chemical, Biological and Macro-Molecular Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700106, India.
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Li B, Wang YL, Shi G, Gao Y, Shi X, Woodward CE, Forsman J. Phase Transitions of Oppositely Charged Colloidal Particles Driven by Alternating Current Electric Field. ACS NANO 2021; 15:2363-2373. [PMID: 33576616 PMCID: PMC8023798 DOI: 10.1021/acsnano.0c04095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We study systems containing oppositely charged colloidal particles under applied alternating current electric fields (AC fields) using overdamped Langevin dynamics simulations in three dimensions. We obtain jammed bands perpendicular to the field direction under intermediate frequencies and lanes parallel with the field under low frequencies. These structures also depend upon the particle charges. The pathway for generating jammed bands follows a stepwise mechanism, and intermediate bands are observed during lane formation in some systems. We investigate the component of the pressure tensors in the direction parallel to the field and observe that the jammed to lane transition occurs at a critical value for this pressure. We also find that the stable steady states appear to satisfy the principle of maximum entropy production. Our results may help to improve the understand of the underlying mechanisms for these types of dynamic phase transitions and the subsequent cooperative assemblies of colloidal particles under such non-equilibrium conditions.
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Affiliation(s)
- Bin Li
- Laboratory
of Theoretical and Computational Nanoscience, CAS Key Laboratory for
Nanosystem and Hierarchy Fabrication, CAS Center for Excellence in
Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, China
- Theoretical
Chemistry, Chemical Center, Lund University, P.O. Box 124, S-221 00 Lund, Sweden
- School
of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, China
| | - Yong-Lei Wang
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Guang Shi
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Yangyang Gao
- Key
Laboratory of Beijing City on Preparation and Processing of Novel
Polymer Materials, Beijing University of
Chemical Technology, Beijing 10029, China
- State Key
Laboratory of Organic−Inorganic Composites, Beijing University of Chemical Technology, Beijing 10029, China
| | - Xinghua Shi
- Laboratory
of Theoretical and Computational Nanoscience, CAS Key Laboratory for
Nanosystem and Hierarchy Fabrication, CAS Center for Excellence in
Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, China
| | - Clifford E. Woodward
- School
of Physical, Environmental and Mathematical Sciences, University College,
ADFA, University of New South Wales, Canberra, ACT 2600, Australia
| | - Jan Forsman
- Theoretical
Chemistry, Chemical Center, Lund University, P.O. Box 124, S-221 00 Lund, Sweden
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Dutta S, Chakrabarti J. Length-scales of dynamic heterogeneity in a driven binary colloid. Phys Chem Chem Phys 2020; 22:17731-17737. [PMID: 32744271 DOI: 10.1039/d0cp02703k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here we study the characteristic length scales in an aqueous suspension of a symmetric oppositely charged colloid subjected to a uniform electric field by Brownian dynamics simulations. We consider the in-plane structure in the presence of a sufficiently strong electric field where the like charges in the system form macroscopic lanes. We construct spatial correlation functions characterizing the structural order and that of particles of different mobilities in the plane transverse to the electric field at a given time. We call these functions equal time density correlation functions (ETDCFs). The ETDCFs between particles of different charges, irrespective of mobilities, are the structural ETDCFs, while those between particles of different mobilities are the dynamic ETDCFs. We extract the characteristic length of correlation by fitting the envelopes of the ETDCFs to exponential dependences. We find that the correlation length scales of the structural ETDCFs and the dynamic ETDCFs of the slow particles increase with time in a concurrent manner. This suggests that the clustering of particles tends to build up dynamically correlated slow particles in the plane transverse to the lanes. The ETDCFs can be measured for colloidal systems by directly following the particle motion by video-microscopy and may be useful to understand the patterns out of equilibrium.
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Affiliation(s)
- Suman Dutta
- S. N. Bose National Centre for Basic Sciences, Blcok-JD, Sector-III, Salt Lake, Kolkata 700 106, India.
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Tendong E, Dasgupta TS, Chakrabarti J. Dynamics of water trapped in transition metal oxide-graphene nano-confinement. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:325101. [PMID: 32191936 DOI: 10.1088/1361-648x/ab814f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 03/19/2020] [Indexed: 06/10/2023]
Abstract
Motivated by practical implementation of transition-metal oxide-graphene heterostructures, we use all atom molecular dynamics simulations to study dynamics of water in a nano slit bounded by a transition metal oxide surface, namely, TiO2termination of SrTiO3, and graphene. The resultant asymmetric, strong confinement produces square ice-like crystallites of water pinned at TiO2surface and drives enhanced hydrophobicity of graphene via the proximity effect to the hydrophilic TiO2surface. This importantly brings in dynamic heterogeneity, both in translational and rotational degrees of freedom, due to coupling between the slow relaxing, strongly adsorbed water layer at the hydrophilic oxide surface, and faster relaxation of subsequent water layers. The heterogeneity is signalled in the ruggedness of the effective free energy landscapes. We discuss possible implications of our findings in drug delivery.
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Affiliation(s)
- E Tendong
- Department of Condensed Matter Physics and Material Sciences & Department of Chemical Biological and Macromoleculer Sciences, S N Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata - 700106, India
| | - T Saha Dasgupta
- Department of Condensed Matter Physics and Material Sciences & Department of Chemical Biological and Macromoleculer Sciences, S N Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata - 700106, India
| | - J Chakrabarti
- Department of Condensed Matter Physics and Material Sciences,Thematic Unit of Excellence for Material Science & Technology Research Centre, S N Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata - 700106, India
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