1
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Hendley RS, Zhang L, Bevan MA. Multistate Dynamic Pathways for Anisotropic Colloidal Assembly and Reconfiguration. ACS NANO 2023; 17:20512-20524. [PMID: 37788439 DOI: 10.1021/acsnano.3c07202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
We report the controlled interfacial assembly and reconfiguration of rectangular prism colloidal particles between microstructures of varying positional and orientational order including stable, metastable, and transient states. Structurally diverse states are realized by programming time dependent electric fields that mediate dipolar interactions determining particle position, orientation, compression, and chaining. We identify an order parameter set that defines each state as a combination of the positional and orientational order. These metrics are employed as reaction coordinates to capture the microstructure evolution between initial and final states upon field changes. Assembly trajectory manifolds between states in the low-dimensional reaction coordinate space reveal a dynamic pathway map including information about pathway accessibility, reversibility, and kinetics. By navigating the dynamic pathway map, we demonstrate reconfiguration between states on minute time scales, which is practically useful for particle-based materials processing and device responses. Our findings demonstrate a conceptually general approach to discover dynamic pathways as a basis to control assembly and reconfiguration of self-organizing building blocks that respond to global external stimuli.
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Affiliation(s)
- Rachel S Hendley
- Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Lechuan Zhang
- Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Michael A Bevan
- Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
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2
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Wang K, Leville S, Behdani B, Silvera Batista CA. Long-range transport and directed assembly of charged colloids under aperiodic electrodiffusiophoresis. SOFT MATTER 2022; 18:5949-5959. [PMID: 35920440 DOI: 10.1039/d2sm00631f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Faradaic reactions often lead to undesirable side effects during the application of electric fields. Therefore, experimental designs often avoid faradaic reactions by working at low voltages or at high frequencies, where the electrodes behave as ideally polarizable. In this work, we show how faradaic processes under ac fields can be used advantageously to effect long-range transport, focusing and assembly of charged colloids. Herein, we use confocal microscopy and ratiometric analysis to confirm that ac fields applied in media of low conductivity induce significant pH gradients below and above the electrode charging frequency of the system. At voltages above 1 Vpp, and frequencies below 1.7 kHz, the pH profile becomes highly nonlinear. Charged particles respond to such conditions by migrating towards the point of highest pH, thereby focusing tens of microns away from both electrodes. Under the combination of oscillating electric fields and concentration gradients of electroactive species, particles experience aperiodic electrodiffusiophoresis (EDP). The theory of EDP, along with a mass transport model, describes the dynamics of particles. Furthermore, the high local concentration of particles near the focusing point leads to disorder-order transitions, whereby particles form crystals. The position and order within the levitating crystalline sheet can be readily tuned by adjusting the voltage and frequency. These results not only have significant implications for the fundamental understanding of ac colloidal electrokinetics, but also provide new possibilities for the manipulation and directed assembly of charged colloids.
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Affiliation(s)
- Kun Wang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA.
| | - Samuel Leville
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA.
| | - Behrouz Behdani
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA.
| | - Carlos A Silvera Batista
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA.
- Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University, Nashville, TN, USA
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3
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Ramírez-Garza OA, Méndez-Alcaraz JM, González-Mozuelos P. Effects of the curvature gradient on the distribution and diffusion of colloids confined to surfaces. Phys Chem Chem Phys 2021; 23:8661-8672. [PMID: 33876027 DOI: 10.1039/d0cp06474b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The properties and behavior of colloids confined to move on curved surfaces offer a fertile ground for analysis since the geometric constraints induce specific features that are not available in flat spaces. Given their pertinence for biological and physicochemical processes, both with potential useful applications, the development of the concepts and methodology necessary for a deeper understanding of these unconventional systems is indeed an essential pursuit. The present study discusses a general and rigorous algorithm for the implementation of Brownian dynamics simulations that solves underlying difficulties and shortcomings inherent to conventional first-order schemes. Still based on the Ermak-McCammon recipe, our approach complements it with the higher-order geodesical projections of the elementary jumps generated on the associated tangent plane. This strategy, which warrants the locally isotropic propagation of non-interacting particles, is tested with a model system of colloidal particles interacting through a screened Coulomb potential while confined to move on ellipsoidal surfaces. This allows us to measure the effects prompted by the curvature gradient on the static and dynamic properties of this system. The varying curvature thus induces energetically favorable configurations in which the particles maximize their Euclidean distancing by crowding the regions with the largest Gaussian curvature, while withdrawing from those with the lowest. In turn, these inhomogeneous distributions provoke the anisotropic self-diffusion of the confined colloids, which is examined by exploiting the pertinent geodesic radial coordinates. The proficient methods under consideration thus allows dealing with the rich and remarkable new phenomena generated by any distinctive surface geometry.
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Affiliation(s)
- O A Ramírez-Garza
- Departamento de Física, Cinvestav del I. P. N., Av. Instituto Politécnico Nacional 2508, Ciudad de México, C. P. 07360, Mexico.
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4
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Maestas JR, Ma F, Wu N, Wu DT. Electric-Field-Driven Assembly of Dipolar Spheres Asymmetrically Confined between Two Electrodes. ACS NANO 2021; 15:2399-2412. [PMID: 33570907 DOI: 10.1021/acsnano.0c04939] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Externally applied electric fields have previously been utilized to direct the assembly of colloidal particles confined at a surface into a large variety of colloidal oligomers and nonclose-packed honeycomb lattices (J. Am. Chem. Soc. 2013, 135, 7839-7842). The colloids under such confinement and fields are observed to spontaneously organize into bilayers near the electrode. To extend and better understand how particles can come together to form quasi-two-dimensional materials, we have performed Monte Carlo simulations and complementary experiments of colloids that are strongly confined between two electrodes under an applied alternating current electric field, controlling field strength and particle area fraction. Of particular importance, we control the fraction of particles in the upper vs lower plane, which we describe as asymmetric confinement, and which effectively modulates the coordination number of particles in each plane. We model the particle-particle interactions using a Stockmayer potential to capture the dipolar interactions induced by the electric field. Phase diagrams are then delineated as a function of the control parameters, and a theoretical model is developed in which the energies of several idealized lattices are calculated and compared. We find that the resulting theoretical phase diagrams agree well with simulation. We have not only reproduced the structures observed in experiments using parameters that are close to experimental conditions but also found several previously unobserved phases in the simulations, including a network of rectangular bands, zig zags, and a sigma lattice, which we were then able to confirm in experiment. We further propose a simple way to precisely control the number ratio of particles between different planes, that is, superimposing a direct current electric field with the alternating current electric field, which can be implemented conveniently in experiments. Our work demonstrates that a diverse collection of materials can be assembled from relatively simple ingredients, which can be analyzed effectively through comparison of simulation, theory, and experiment. Our model further explains possible pathways between different phases and provides a platform for examining phases that have yet to be observed in experiments.
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Affiliation(s)
- Joseph R Maestas
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Fuduo Ma
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Ning Wu
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - David T Wu
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
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5
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Zhang J, Yang J, Zhang Y, Bevan MA. Controlling colloidal crystals via morphing energy landscapes and reinforcement learning. SCIENCE ADVANCES 2020; 6:6/48/eabd6716. [PMID: 33239301 PMCID: PMC7688337 DOI: 10.1126/sciadv.abd6716] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 10/02/2020] [Indexed: 05/23/2023]
Abstract
We report a feedback control method to remove grain boundaries and produce circular shaped colloidal crystals using morphing energy landscapes and reinforcement learning-based policies. We demonstrate this approach in optical microscopy and computer simulation experiments for colloidal particles in ac electric fields. First, we discover how tunable energy landscape shapes and orientations enhance grain boundary motion and crystal morphology relaxation. Next, reinforcement learning is used to develop an optimized control policy to actuate morphing energy landscapes to produce defect-free crystals orders of magnitude faster than natural relaxation times. Morphing energy landscapes mechanistically enable rapid crystal repair via anisotropic stresses to control defect and shape relaxation without melting. This method is scalable for up to at least N = 103 particles with mean process times scaling as N 0.5 Further scalability is possible by controlling parallel local energy landscapes (e.g., periodic landscapes) to generate large-scale global defect-free hierarchical structures.
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Affiliation(s)
- Jianli Zhang
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Junyan Yang
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Yuanxing Zhang
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Michael A Bevan
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
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6
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Yang Y, Bevan MA, Li B. Micro/Nano Motor Navigation and Localization via Deep Reinforcement Learning. ADVANCED THEORY AND SIMULATIONS 2020. [DOI: 10.1002/adts.202000034] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Yuguang Yang
- Institute of Biomechanics and Medical EngineeringApplied Mechanics LaboratoryDepartment of Engineering MechanicsTsinghua University Beijing 100084 China
- Chemical & Biomolecular EngineeringJohns Hopkins University Baltimore MD 21218 USA
| | - Michael A. Bevan
- Chemical & Biomolecular EngineeringJohns Hopkins University Baltimore MD 21218 USA
| | - Bo Li
- Institute of Biomechanics and Medical EngineeringApplied Mechanics LaboratoryDepartment of Engineering MechanicsTsinghua University Beijing 100084 China
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7
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Zhang J, Zhang Y, Bevan MA. Spatially varying colloidal phase behavior on multi-dimensional energy landscapes. J Chem Phys 2020; 152:054905. [DOI: 10.1063/1.5142609] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Jianli Zhang
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Yuanxing Zhang
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Michael A. Bevan
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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8
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Yang Y, Li B. A simulation algorithm for Brownian dynamics on complex curved surfaces. J Chem Phys 2019; 151:164901. [PMID: 31675869 DOI: 10.1063/1.5126201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Brownian dynamics of colloidal particles on complex curved surfaces has found important applications in diverse physical, chemical, and biological processes. However, most Brownian dynamics simulation algorithms focus on relatively simple curved surfaces that can be analytically parameterized. In this work, we develop an algorithm to enable Brownian dynamics simulation on extremely complex curved surfaces. We approximate complex curved surfaces with triangle mesh surfaces and employ a novel scheme to perform particle simulation on these triangle mesh surfaces. Our algorithm computes forces and velocities of particles in global coordinates but updates their positions in local coordinates, which combines the strengths from both global and local simulation schemes. We benchmark the proposed algorithm with theory and then simulate Brownian dynamics of both single and multiple particles on torus and knot surfaces. The results show that our method captures well diffusion, transport, and crystallization of colloidal particles on complex surfaces with nontrivial topology. This study offers an efficient strategy for elucidating the impact of curvature, geometry, and topology on particle dynamics and microstructure formation in complex environments.
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Affiliation(s)
- Yuguang Yang
- Institute of Biomechanics and Medical Engineering, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Bo Li
- Institute of Biomechanics and Medical Engineering, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
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9
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Altemose A, Harris AJ, Sen A. Autonomous Formation and Annealing of Colloidal Crystals Induced by Light‐Powered Oscillations of Active Particles. CHEMSYSTEMSCHEM 2019. [DOI: 10.1002/syst.201900021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Alicia Altemose
- Department of Chemistry The Pennsylvania State University 104 Chemistry Building, University Park, PA USA
| | - Aaron J. Harris
- Independent researcher 910 Louisiana St., Suite 8052B Houston, TX USA
| | - Ayusman Sen
- Department of Chemistry The Pennsylvania State University 104 Chemistry Building, University Park, PA USA
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10
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Coughlan ACH, Torres-Díaz I, Zhang J, Bevan MA. Non-equilibrium steady-state colloidal assembly dynamics. J Chem Phys 2019; 150:204902. [PMID: 31153195 DOI: 10.1063/1.5094554] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Simulations and experiments are reported for nonequilibrium steady-state assembly of small colloidal crystal clusters in rotating magnetic fields vs frequency and amplitude. High-dimensional trajectories of particle coordinates from image analysis of experiments and from Stokesian Dynamic computer simulations are fit to low-dimensional reaction coordinate based Fokker-Planck and Langevin equations. The coefficients of these equations are effective energy and diffusivity landscapes that capture configuration-dependent energy and friction for nonequilibrium steady-state dynamics. Two reaction coordinates that capture condensation and anisotropy of dipolar chains folding into crystals are sufficient to capture high-dimensional experimental and simulated dynamics in terms of first passage time distributions. Our findings illustrate how field-mediated nonequilibrium steady-state colloidal assembly dynamics can be modeled to interpret and design pathways toward target microstructures and morphologies.
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Affiliation(s)
- Anna C H Coughlan
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Isaac Torres-Díaz
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Jianli Zhang
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Michael A Bevan
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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11
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Komarov KA, Kryuchkov NP, Yurchenko SO. Tunable interactions between particles in conically rotating electric fields. SOFT MATTER 2018; 14:9657-9674. [PMID: 30457624 DOI: 10.1039/c8sm01538d] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Tunable interactions between colloidal particles in external conically rotating electric fields are calculated, while the (vertical) axis of the field rotation is normal to the (horizontal) particle motion plane. The comparison of different approaches, including the methods of noninteracting, self-consistent dipoles, and the boundary element method, indicates that the last method is the most suitable for tunable interaction analysis. Thorough analysis, performed for interactions in pairs and clusters of colloidal particles, indicate that two- and three-body interactions make the main contributions in the interaction energy, while the effect of high-order terms is negligible. The tunable interactions are determined by the dielectric properties of the particles and solvent and can be changed in a wide range, providing a rich variety for the experimental "design" of different interactions, including repulsion, attraction, combination of short-range repulsion with long-range attraction, barrier-type interactions with short-range attraction and long-range repulsion, and double-scale repulsive (core-shoulder) interactions. These conclusions can be generalized for magnetically induced tunable interactions. The results indicate that tunable interactions can be widely applied in self-assembly and particle-resolved studies of generic phenomena in fluids and crystals, and, therefore, are of broad interest in the fields of chemical physics, physical chemistry, materials science, and soft matter.
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Affiliation(s)
- Kirill A Komarov
- Bauman Moscow State Technical University, 2nd Baumanskaya street 5, 105005 Moscow, Russia.
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12
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Solomon MJ. Tools and Functions of Reconfigurable Colloidal Assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:11205-11219. [PMID: 29397742 DOI: 10.1021/acs.langmuir.7b03748] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We review work in reconfigurable colloidal assembly, a field in which rapid, back-and-forth transitions between the equilibrium states of colloidal self-assembly are accomplished by dynamic manipulation of the size, shape, and interaction potential of colloids, as well as the magnitude and direction of the fields applied to them. It is distinguished from the study of colloidal phase transitions by the centrality of thermodynamic variables and colloidal properties that are time switchable; by the applicability of these changes to generate transitions in assembled colloids that may be spatially localized; and by its incorporation of the effects of generalized potentials due to, for example, applied electric and magnetic fields. By drawing upon current progress in the field, we propose a matrix classification of reconfigurable colloidal systems based on the tool used and function performed by reconfiguration. The classification distinguishes between the multiple means by which reconfigurable assembly can be accomplished (i.e., the tools of reconfiguration) and the different kinds of structural transitions that can be achieved by it (i.e., the functions of reconfiguration). In the first case, the tools of reconfiguration can be broadly classed as (i) those that control the colloidal contribution to the system entropy-as through volumetric and/or shape changes of the particles; (ii) those that control the internal energy of the colloids-as through manipulation of colloidal interaction potentials; and (iii) those that control the spatially resolved potential energy that is imposed on the colloids-as through the introduction of field-induced phoretic mechanisms that yield colloidal displacement and accumulation. In the second case, the functions of reconfiguration include reversible: (i) transformation between different phases-including fluid, cluster, gel, and crystal structures; (ii) manipulation of the spacing between colloids in crystals and clusters; and (iii) translation, rotation, or shape-change of finite-size objects self-assembled from colloids. With this classification in hand, we correlate the current limits on the spatiotemporal scales for reconfigurable colloidal assembly and identify a set of future research challenges.
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13
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Stoop N, Dunkel J. Defect formation dynamics in curved elastic surface crystals. SOFT MATTER 2018; 14:2329-2338. [PMID: 29487938 DOI: 10.1039/c7sm02233f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Topological defects shape the material and transport properties of physical systems. Examples range from vortex lines in quantum superfluids, defect-mediated buckling of graphene, and grain boundaries in ferromagnets and colloidal crystals, to domain structures formed in the early universe. The Kibble-Zurek (KZ) mechanism describes the topological defect formation in continuous non-equilibrium phase transitions with a constant finite quench rate. Universal KZ scaling laws have been verified experimentally and numerically for second-order transitions in planar Euclidean geometries, but their validity for non-thermal transitions in curved and topologically nontrivial systems still poses open questions. Here, we use recent experimentally confirmed theory to investigate topological defect formation in curved elastic surface crystals formed by stress-quenching a bilayer material. For both spherical and toroidal crystals, we find that the defect densities follow KZ-type power laws. Moreover, the nucleation sequences agree with recent experimental observations for spherical colloidal crystals. Our results suggest that curved elastic bilayers provide an experimentally accessible macroscopic system to study universal properties of non-thermal phase transitions in non-planar geometries.
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Affiliation(s)
- Norbert Stoop
- Department of Mathematics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139-4307, USA.
| | - Jörn Dunkel
- Department of Mathematics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139-4307, USA.
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14
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Kryuchkov NP, Yurchenko SO, Fomin YD, Tsiok EN, Ryzhov VN. Complex crystalline structures in a two-dimensional core-softened system. SOFT MATTER 2018; 14:2152-2162. [PMID: 29488995 DOI: 10.1039/c7sm02429k] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A transition from a square to a hexagonal lattice is studied in a 2D system of particles interacting via a core-softened potential. Due to the presence of two length scales of repulsion, different local configurations with four, five, and six neighbors are possible, leading to the formation of complex crystals. The previously proposed interpolation method is generalized to calculate pair correlations in crystals whose unit cell consists of more than one particle. The high efficiency of the method is illustrated using a snub square lattice as a representative example. Molecular dynamics simulations show that the snub square lattice is broken upon heating, generating a high-density quasicrystalline phase with 12-fold symmetry (HD12 phase). A simple theoretical model is proposed to explain the physical mechanism responsible for this phenomenon: with an increase in the density (from square to hexagonal phases), the concentrations of different local configurations randomly realized through a plane tiling change, which minimizes the energy of the system. The calculated phase diagram in the intermediate density range justifies the existence of the HD12 phase and demonstrates a cascade of first-order transitions "square - HD12 - hexagonal" solid phases with increasing density. The results allow us to better understand the physical mechanisms responsible for the formation of quasicrystals, and, therefore, should be of interest for broad community in materials science and soft matter.
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Affiliation(s)
- Nikita P Kryuchkov
- Bauman Moscow State Technical University, 2nd Baumanskaya Street 5, 105005 Moscow, Russia.
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15
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Tunable two-dimensional assembly of colloidal particles in rotating electric fields. Sci Rep 2017; 7:13727. [PMID: 29062107 PMCID: PMC5653874 DOI: 10.1038/s41598-017-14001-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 10/03/2017] [Indexed: 11/18/2022] Open
Abstract
Tunable interparticle interactions in colloidal suspensions are of great interest because of their fundamental and practical significance. In this paper we present a new experimental setup for self-assembly of colloidal particles in two-dimensional systems, where the interactions are controlled by external rotating electric fields. The maximal magnitude of the field in a suspension is 25 V/mm, the field homogeneity is better than 1% over the horizontal distance of 250 μm, and the rotation frequency is in the range of 40 Hz to 30 kHz. Based on numerical electrostatic calculations for the developed setup with eight planar electrodes, we found optimal experimental conditions and performed demonstration experiments with a suspension of 2.12 μm silica particles in water. Thanks to its technological flexibility, the setup is well suited for particle-resolved studies of fundamental generic phenomena occurring in classical liquids and solids, and therefore it should be of interest for a broad community of soft matter, photonics, and material science.
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16
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Giera B, Zepeda-Ruiz LA, Pascall AJ, Weisgraber TH. Mesoscale Particle-Based Model of Electrophoretic Deposition. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:652-661. [PMID: 27997803 DOI: 10.1021/acs.langmuir.6b04010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present and evaluate a semiempirical particle-based model of electrophoretic deposition using extensive mesoscale simulations. We analyze particle configurations in order to observe how colloids accumulate at the electrode and arrange into deposits. In agreement with existing continuum models, the thickness of the deposit increases linearly in time during deposition. Resulting colloidal deposits exhibit a transition between highly ordered and bulk disordered regions that can give rise to an appreciable density gradient under certain simulated conditions. The overall volume fraction increases and falls within a narrow range as the driving force due to the electric field increases and repulsive intercolloidal interactions decrease. We postulate ordering and stacking within the initial layer(s) dramatically impacts the microstructure of the deposits. We find a combination of parameters, i.e., electric field and suspension properties, whose interplay enhances colloidal ordering beyond the commonly known approach of only reducing the driving force.
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Affiliation(s)
- Brian Giera
- Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Luis A Zepeda-Ruiz
- Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Andrew J Pascall
- Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Todd H Weisgraber
- Lawrence Livermore National Laboratory, Livermore, California 94550, United States
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17
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Bui PT, Hoang TX. Folding and escape of nascent proteins at ribosomal exit tunnel. J Chem Phys 2016; 144:095102. [PMID: 26957181 DOI: 10.1063/1.4943042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We investigate the interplay between post-translational folding and escape of two small single-domain proteins at the ribosomal exit tunnel by using Langevin dynamics with coarse-grained models. It is shown that at temperatures lower or near the temperature of the fastest folding, folding proceeds concomitantly with the escape process, resulting in vectorial folding and enhancement of foldability of nascent proteins. The concomitance between the two processes, however, deteriorates as temperature increases. Our folding simulations as well as free energy calculation by using umbrella sampling show that, at low temperatures, folding at the tunnel follows one or two specific pathways without kinetic traps. It is shown that the escape time can be mapped to a one-dimensional diffusion model with two different regimes for temperatures above and below the folding transition temperature. Attractive interactions between amino acids and attractive sites on the tunnel wall lead to a free energy barrier along the escape route of the protein. It is suggested that this barrier slows down the escape process and consequently promotes correct folding of the released nascent protein.
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Affiliation(s)
- Phuong Thuy Bui
- Center for Computational Physics, Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan, Ba Dinh, Hanoi, Vietnam
| | - Trinh Xuan Hoang
- Center for Computational Physics, Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan, Ba Dinh, Hanoi, Vietnam
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18
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Pham AT, Seto R, Schönke J, Joh DY, Chilkoti A, Fried E, Yellen BB. Crystallization kinetics of binary colloidal monolayers. SOFT MATTER 2016; 12:7735-7746. [PMID: 27477956 DOI: 10.1039/c6sm01072e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Experiments and simulations are used to study the kinetics of crystal growth in a mixture of magnetic and nonmagnetic particles suspended in ferrofluid. The growth process is quantified using both a bond order parameter and a mean domain size parameter. The largest single crystals obtained in experiments consist of approximately 1000 particles and form if the area fraction is held between 65-70% and the field strength is kept in the range of 8.5-10.5 Oe. Simulations indicate that much larger single crystals containing as many as 5000 particles can be obtained under impurity-free conditions within a few hours. If our simulations are modified to include impurity concentrations as small as 1-2%, then the results agree quantitatively with the experiments. These findings provide an important step toward developing strategies for growing single crystals that are large enough to enable follow-on investigations across many subdisciplines in condensed matter physics.
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Affiliation(s)
- An T Pham
- Department of Mechanical Engineering and Materials Science, Duke University, Box 90300 Hudson Hall, Durham, NC 27708, USA.
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19
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Tang X, Rupp B, Yang Y, Edwards TD, Grover MA, Bevan MA. Optimal Feedback Controlled Assembly of Perfect Crystals. ACS NANO 2016; 10:6791-6798. [PMID: 27387146 DOI: 10.1021/acsnano.6b02400] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Perfectly ordered states are targets in diverse molecular to microscale systems involving, for example, atomic clusters, protein folding, protein crystallization, nanoparticle superlattices, and colloidal crystals. However, there is no obvious approach to control the assembly of perfectly ordered global free energy minimum structures; near-equilibrium assembly is impractically slow, and faster out-of-equilibrium processes generally terminate in defective states. Here, we demonstrate the rapid and robust assembly of perfect crystals by navigating kinetic bottlenecks using closed-loop control of electric field mediated crystallization of colloidal particles. An optimal policy is computed with dynamic programming using a reaction coordinate based dynamic model. By tracking real-time stochastic particle configurations and adjusting applied fields via feedback, the evolution of unassembled particles is guided through polycrystalline states into single domain crystals. This approach to controlling the assembly of a target structure is based on general principles that make it applicable to a broad range of processes from nano- to microscales (where tuning a global thermodynamic variable yields temporal control over thermal sampling of different states via their relative free energies).
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Affiliation(s)
- Xun Tang
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Bradley Rupp
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Yuguang Yang
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Tara D Edwards
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Martha A Grover
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Michael A Bevan
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States
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Yang Y, Thyagarajan R, Ford DM, Bevan MA. Dynamic colloidal assembly pathways via low dimensional models. J Chem Phys 2016; 144:204904. [DOI: 10.1063/1.4951698] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yuguang Yang
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Raghuram Thyagarajan
- Chemical Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - David M. Ford
- Chemical Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Michael A. Bevan
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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Colloidal Crystallization in 2D for Short-Ranged Attractions: A Descriptive Overview. CRYSTALS 2016. [DOI: 10.3390/cryst6040046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Ni S, Leemann J, Buttinoni I, Isa L, Wolf H. Programmable colloidal molecules from sequential capillarity-assisted particle assembly. SCIENCE ADVANCES 2016; 2:e1501779. [PMID: 27051882 PMCID: PMC4820371 DOI: 10.1126/sciadv.1501779] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 02/13/2016] [Indexed: 05/19/2023]
Abstract
The assembly of artificial nanostructured and microstructured materials which display structures and functionalities that mimic nature's complexity requires building blocks with specific and directional interactions, analogous to those displayed at the molecular level. Despite remarkable progress in synthesizing "patchy" particles encoding anisotropic interactions, most current methods are restricted to integrating up to two compositional patches on a single "molecule" and to objects with simple shapes. Currently, decoupling functionality and shape to achieve full compositional and geometrical programmability remains an elusive task. We use sequential capillarity-assisted particle assembly which uniquely fulfills the demands described above. This is a new method based on simple, yet essential, adaptations to the well-known capillary assembly of particles over topographical templates. Tuning the depth of the assembly sites (traps) and the surface tension of moving droplets of colloidal suspensions enables controlled stepwise filling of traps to "synthesize" colloidal molecules. After deposition and mechanical linkage, the colloidal molecules can be dispersed in a solvent. The template's shape solely controls the molecule's geometry, whereas the filling sequence independently determines its composition. No specific surface chemistry is required, and multifunctional molecules with organic and inorganic moieties can be fabricated. We demonstrate the "synthesis" of a library of structures, ranging from dumbbells and triangles to units resembling bar codes, block copolymers, surfactants, and three-dimensional chiral objects. The full programmability of our approach opens up new directions not only for assembling and studying complex materials with single-particle-level control but also for fabricating new microscale devices for sensing, patterning, and delivery applications.
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Affiliation(s)
- Songbo Ni
- Laboratory for Interfaces, Soft Matter, and Assembly, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, 8093 Zurich, Switzerland
- IBM Research–Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Jessica Leemann
- Laboratory for Interfaces, Soft Matter, and Assembly, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, 8093 Zurich, Switzerland
- IBM Research–Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Ivo Buttinoni
- Laboratory for Interfaces, Soft Matter, and Assembly, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, 8093 Zurich, Switzerland
| | - Lucio Isa
- Laboratory for Interfaces, Soft Matter, and Assembly, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, 8093 Zurich, Switzerland
- Corresponding author. E-mail: (L.I.); (H.W.)
| | - Heiko Wolf
- IBM Research–Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
- Corresponding author. E-mail: (L.I.); (H.W.)
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