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Voulgarakis NK. Multilayered noise model for transport in complex environments. Phys Rev E 2023; 108:064105. [PMID: 38243501 DOI: 10.1103/physreve.108.064105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 11/09/2023] [Indexed: 01/21/2024]
Abstract
Transport in complex fluidic environments often exhibits transient subdiffusive dynamics accompanied by non-Gaussian probability density profiles featuring a nonmonotonic non-Gaussian parameter. Such properties cannot be adequately explained by the original theory of Brownian motion. Based on an extension of kinetic theory, this study introduces a chain of hierarchically coupled random walks approach that effectively captures all these intriguing characteristics. If the environment consists of a series of independent white noise sources, then the problem can be expressed as a system of hierarchically coupled Ornstein-Uhlenbech equations. Due to the linearity of the system, the most essential transport properties have a closed analytical form.
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Affiliation(s)
- Nikolaos K Voulgarakis
- Department of Mathematics and Statistics, Washington State University, Pullman, Washington 99164, USA
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Kim EC, Chun DJ, Park CB, Sung BJ. Machine learning predicts the glass transition of two-dimensional colloids besides medium-range crystalline order. Phys Rev E 2023; 108:044602. [PMID: 37978710 DOI: 10.1103/physreve.108.044602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 08/10/2023] [Indexed: 11/19/2023]
Abstract
We employ only the positions of colloidal particles and construct machine learning (ML) models to test the presence of structural order in glass transition for two kinds of two-dimensional (2D) colloids: 2D polydisperse colloids (PC) with medium-range crystalline order (MRCO) and 2D binary colloids (BC) without MRCO. ML models predict the glass transition of 2D colloids successfully without any information on MRCO. Even certain ML models trained with BC predict the glass transition of PC successfully, thus suggesting that universal structural characteristics would exist besides MRCO.
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Affiliation(s)
- Eun Cheol Kim
- Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea
| | - Dong Jae Chun
- Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea
| | - Chung Bin Park
- Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea
| | - Bong June Sung
- Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea
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Dai LJ, Fu CL, Zhu YL, Li ZW, Sun ZY. Probing Intermittent Motion of Polymer Chains in Weakly Attractive Nanocomposites. CHINESE JOURNAL OF POLYMER SCIENCE 2019. [DOI: 10.1007/s10118-020-2352-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Roberts RC, Poling-Skutvik R, Conrad JC, Palmer JC. Tracer transport in attractive and repulsive supercooled liquids and glasses. J Chem Phys 2019; 151:194501. [DOI: 10.1063/1.5121851] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ryan C. Roberts
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, USA
| | - Ryan Poling-Skutvik
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Jacinta C. Conrad
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, USA
| | - Jeremy C. Palmer
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, USA
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6
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Abstract
AbstractThe dynamics of proteins in solution includes a variety of processes, such as backbone and side-chain fluctuations, interdomain motions, as well as global rotational and translational (i.e. center of mass) diffusion. Since protein dynamics is related to protein function and essential transport processes, a detailed mechanistic understanding and monitoring of protein dynamics in solution is highly desirable. The hierarchical character of protein dynamics requires experimental tools addressing a broad range of time- and length scales. We discuss how different techniques contribute to a comprehensive picture of protein dynamics, and focus in particular on results from neutron spectroscopy. We outline the underlying principles and review available instrumentation as well as related analysis frameworks.
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Dai LJ, Fu CL, Zhu YL, Sun ZY. Heterogeneous dynamics of unentangled chains in polymer nanocomposites. J Chem Phys 2019; 150:184903. [PMID: 31091923 DOI: 10.1063/1.5089816] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We present a systematic investigation on the effect of adding nanoparticles on the dynamics of polymer chains by using coarse-grained molecular dynamics simulation. The dynamics is characterized by three aspects: molecular motion, relaxation at different length scales, and dynamical heterogeneity. It is found that the motion of polymer chains slows down and the deviation from Gaussian distribution becomes more pronounced with increasing nanoparticle volume fractions. For polymer nanocomposites with R ≤ Rg, the relaxation at the wave vector q = 7.0 displays multistep decay, consistent with the previous reports in strongly interacting polymer nanocomposites. Moreover, a qualitatively universal law is established that dynamic heterogeneity at whole chain's scale follows a nonmonotonic increase with increasing nanoparticle loadings, where the volume fraction of the maximum dynamic heterogeneity corresponds to the particle loading when the average distance between nanoparticles is equal to the Kuhn length of polymer chains. We show that the decoupling between whole chain's dynamics and segment dynamics is responsible for the nonmonotonic behavior of dynamic heterogeneity of whole chains.
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Affiliation(s)
- Li-Jun Dai
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Cui-Liu Fu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - You-Liang Zhu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Zhao-Yan Sun
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
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Luo B, Kim A, Smith JW, Ou Z, Wu Z, Kim J, Chen Q. Hierarchical self-assembly of 3D lattices from polydisperse anisometric colloids. Nat Commun 2019; 10:1815. [PMID: 31000717 PMCID: PMC6472373 DOI: 10.1038/s41467-019-09787-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 03/21/2019] [Indexed: 01/22/2023] Open
Abstract
Colloids are mainly divided into two types defined by size. Micron-scale colloids are widely used as model systems to study phase transitions, while nanoparticles have physicochemical properties unique to their size. Here we study a promising yet underexplored third type: anisometric colloids, which integrate micrometer and nanometer dimensions into the same particle. We show that our prototypical system of anisometric silver plates with a high polydispersity assemble, unexpectedly, into an ordered, three-dimensional lattice. Real-time imaging and interaction modeling elucidate the crucial role of anisometry, which directs hierarchical assembly into secondary building blocks-columns-which are sufficiently monodisperse for further ordering. Ionic strength and plate tip morphology control the shape of the columns, and therefore the final lattice structures (hexagonal versus honeycomb). Our joint experiment-modeling study demonstrates potentials of encoding unconventional assembly in anisometric colloids, which can likely introduce properties and phase behaviors inaccessible to micron- or nanometer-scale colloids.
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Affiliation(s)
- Binbin Luo
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL, 61801, USA
| | - Ahyoung Kim
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL, 61801, USA
| | - John W Smith
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL, 61801, USA
| | - Zihao Ou
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL, 61801, USA
| | - Zixuan Wu
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL, 61801, USA
| | - Juyeong Kim
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL, 61801, USA
- Materials Research Laboratory, University of Illinois, Urbana, IL, 61801, USA
- Department of Chemistry and Research Institute of Natural Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Qian Chen
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL, 61801, USA.
- Materials Research Laboratory, University of Illinois, Urbana, IL, 61801, USA.
- Department of Chemistry, University of Illinois, Urbana, IL, 61801, USA.
- Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, IL, 61801, USA.
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Differential dynamic microscopy of bidisperse colloidal suspensions. NPJ Microgravity 2017; 3:21. [PMID: 28868354 PMCID: PMC5577322 DOI: 10.1038/s41526-017-0027-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 06/10/2017] [Accepted: 06/16/2017] [Indexed: 02/02/2023] Open
Abstract
Research tasks in microgravity include monitoring the dynamics of constituents of varying size and mobility in processes such as aggregation, phase separation, or self-assembly. We use differential dynamic microscopy, a method readily implemented with equipment available on the International Space Station, to simultaneously resolve the dynamics of particles of radius 50 nm and 1 μm in bidisperse aqueous suspensions. Whereas traditional dynamic light scattering fails to detect a signal from the larger particles at low concentrations, differential dynamic microscopy exhibits enhanced sensitivity in these conditions by accessing smaller wavevectors where scattering from the large particles is stronger. Interference patterns due to scattering from the large particles induce non-monotonic decay of the amplitude of the dynamic correlation function with the wavevector. We show that the position of the resulting minimum contains information on the vertical position of the particles. Together with the simple instrumental requirements, the enhanced sensitivity of differential dynamic microscopy makes it an appealing alternative to dynamic light scattering to characterize samples with complex dynamics.
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