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Kumar P, Chakrabarti R. Escape dynamics of a self-propelled nanorod from circular confinements with narrow openings. SOFT MATTER 2023; 19:6743-6753. [PMID: 37623699 DOI: 10.1039/d3sm00723e] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
We perform computer simulations to explore the escape dynamics of a self-propelled (active) nanorod from circular confinements with narrow opening(s). Our results clearly demonstrate how the persistent and directed motion of the nanorod helps it to escape. Such escape events are absent if the nanorod is passive. To quantify the escape dynamics, we compute the radial probability density function (RPDF) and mean first escape time (MFET) and show how the activity is responsible for the bimodality of RPDF, which is clearly absent if the nanorod is passive. Broadening of displacement distributions with activity has also been observed. The computed mean first escape time decreases with activity. In contrast, the fluctuations of the first escape times vary in a non-monotonic way. This results in high values of the coefficient of variation and indicates the presence of multiple timescales in first escape time distributions and multimodality in uniformity index distributions. We hope our study will help in differentiating activity-driven escape dynamics from purely thermal passive diffusion in confinement.
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Affiliation(s)
- Praveen Kumar
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India.
| | - Rajarshi Chakrabarti
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India.
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Ghosh PK, Zhou Y, Li Y, Marchesoni F, Nori F. Binary Mixtures in Linear Convection Arrays. Chemphyschem 2023; 24:e202200471. [PMID: 36125421 DOI: 10.1002/cphc.202200471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/19/2022] [Indexed: 01/07/2023]
Abstract
We numerically investigated the dynamics of a mixture of finite-size active and passive disks in a linear array of two-dimensional convection rolls. The interplay of advection and steric interactions produces a number of interesting effects, like the stirring of a passive colloidal fluid by a small fraction of slow active particles, or the separation of the mixture active and passive colloidal fractions by increasing the motility of the active one, which eventually clusters in stagnation areas along the array walls. These mechanisms are quantitatively characterized by studying the dependence of the diffusion constants of the active and passive particles on the parameters of the active mixture fraction.
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Affiliation(s)
- Pulak K Ghosh
- Department of Chemistry, Presidency University, Kolkata, 700073, India
| | - Yuxin Zhou
- Center for Phononics and Thermal Energy Science, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Yunyun Li
- Center for Phononics and Thermal Energy Science, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Fabio Marchesoni
- Center for Phononics and Thermal Energy Science, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai, 200092, China.,Dipartimento di Fisica, Università di Camerino, I-62032, Camerino
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama, 351-0198, Japan.,Physics Department, University of Michigan, Ann Arbor, Michigan, 48109-1040, USA
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Barakat JM, Takatori SC. Enhanced dispersion in an oscillating array of harmonic traps. Phys Rev E 2023; 107:014601. [PMID: 36797955 DOI: 10.1103/physreve.107.014601] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/13/2022] [Indexed: 06/18/2023]
Abstract
Experiment, theory, and simulation are employed to understand the dispersion of colloidal particles in a periodic array of oscillating harmonic traps generated by optical tweezers. In the presence of trap oscillation, a nonmonotonic and anisotropic dispersion is observed. Surprisingly, the stiffest traps produce the largest dispersion at a critical frequency, and the particles diffuse significantly faster in the direction of oscillation than those undergoing passive Stokes-Einstein-Sutherland diffusion. Theoretical predictions for the effective diffusivity of the particles as a function of trap stiffness and oscillation frequency are developed using generalized Taylor dispersion theory and Brownian dynamics simulations. Both theory and simulation demonstrate excellent agreement with the experiments, and reveal a "slingshot" mechanism that predicts a significant enhancement of colloidal diffusion in dynamic external fields.
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Affiliation(s)
- Joseph M Barakat
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - Sho C Takatori
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93106, USA
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Bag P, Nayak S, Debnath T, Ghosh PK. Directed Autonomous Motion and Chiral Separation of Self-Propelled Janus Particles in Convection Roll Arrays. J Phys Chem Lett 2022; 13:11413-11418. [PMID: 36459443 DOI: 10.1021/acs.jpclett.2c03193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Self-propelled Janus particles exhibit autonomous motion thanks to engines of their own. However, due to the randomly changing direction of such motion they are of little use for emerging nanotechnological and biomedical applications. Here, we numerically show that the motion of chiral active Janus particles can be directed, subjecting them to a linear array of convection rolls. The rectification power of self-propulsion motion here can be made to be more than 60%, which is much larger than earlier reports. We show that rectification of a chiral Janus particle's motion leads to conspicuous segregation of dextrogyre and levogyre active particles from a racemic binary mixture. Further, we demonstrate how efficiently the rectification effect can be exploited to separate dextrogyre and levogyre particles when their intrinsic torques are distributed with Gaussian statistics.
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Affiliation(s)
- Poulami Bag
- Department of Chemistry, Presidency University, Kolkata700073, India
| | - Shubhadip Nayak
- Department of Chemistry, Presidency University, Kolkata700073, India
| | - Tanwi Debnath
- Department of Chemistry, University of Calcutta, Kolkata700009, India
| | - Pulak K Ghosh
- Department of Chemistry, Presidency University, Kolkata700073, India
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Kichatov B, Korshunov A, Sudakov V, Golubkov A, Gubernov V, Kiverin A. Motion of a chemically reactive bimetal motor in a magnetic field. Phys Chem Chem Phys 2022; 24:19693-19696. [PMID: 35968933 DOI: 10.1039/d2cp03383f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The wide research interest in nano-, micro-, and macromotors is due to the diverse range of applied problems in engineering, biomedicine, and ecology. At the same time, the amount of known mechanisms responsible for the locomotion of motors is limited. Here, we demonstrate a novel method of motor locomotion, which can be contingently called "chemical magnetism". The phenomenon considered here is based on the fact that any current loop in the magnetic field is affected by a force. "Chemical magnet" represents a bimetal surfer swimming at the electrolyte surface. When the redox reaction proceeds, a current loop emerges. That defines the action of the additional magnetic force on the surfer in the non-uniform magnetic field. The magnetic properties of the surfer can be varied in a wide range by changing the concentration of the electrolyte solution, its temperature, and the pair of metals composing the surfer. The phenomenon of "chemical magnetism" considered here widens a list of known mechanisms of motor locomotion.
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Affiliation(s)
- Boris Kichatov
- Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia.
| | - Alexey Korshunov
- Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia.
| | - Vladimir Sudakov
- Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia.
| | - Alexandr Golubkov
- Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia.
| | - Vladimir Gubernov
- Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia.
| | - Alexey Kiverin
- Joint Institute for High Temperatures, Russian Academy of Sciences, 125412 Moscow, Russia
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Li Y, Zhou Y, Marchesoni F, Ghosh PK. Colloidal clustering and diffusion in a convection cell array. SOFT MATTER 2022; 18:4778-4785. [PMID: 35703429 DOI: 10.1039/d2sm00500j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We numerically investigated the clustering of a uniform suspension of finite-size disks in a linear array of two-dimensional convection cells. We observed that, due to steric interactions, the disks tend to form coherently rotating spatial structures at the center of each cell, as a combined effect of advection and pair collisions. Micellar, ring-like and hexatic patterns emerge in the deterministic regime, depending on the suspension density, but dissolve in the presence of thermal fluctuations. Moreover, pair collisions suffice to activate cell crossings even by noiseless disks and, therefore, cause athermal diffusion. The robustness of such collision induced effects is studied against the opposing action of thermal noise, transverse biases, and particle self-propulsion.
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Affiliation(s)
- Yunyun Li
- Center for Phononics and Thermal Energy Science, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yuxin Zhou
- Center for Phononics and Thermal Energy Science, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Fabio Marchesoni
- Center for Phononics and Thermal Energy Science, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
- Dipartimento di Fisica, Università di Camerino, I-62032 Camerino, Italy.
| | - Pulak K Ghosh
- Department of Chemistry, Presidency University, Kolkata 700073, India.
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