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Zhang H, Feng X, Xia X, Zhu J, Wang H, Ni R, Zhang Z. Shape-Dictated Self-Assembly of Photoresponsive Hybrid Colloids. SMALL METHODS 2023; 7:e2300383. [PMID: 37183306 DOI: 10.1002/smtd.202300383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Indexed: 05/16/2023]
Abstract
The shape-dictated self-assembly of hybrid colloids induced by chemical concentration gradients generated by photocatalytic reactions of the colloids is studied. Different shapes enable the formation of assemblies with distinct lattice structures including hexagons, distorted hexagons, and squares, which are corroborated by computer simulations. Furthermore, assemblies change from lattices to chains when increasing the attraction between the colloids. The results show that photoresponsive hybrid colloids possess a unique capability for shape-dependent self-assembly, offering a practical and versatile approach to manipulate self-assembly at the microscale.
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Affiliation(s)
- Haiyang Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Xuan Feng
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, 637459, Singapore
| | - Xiuyang Xia
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, 637459, Singapore
| | - Jiao Zhu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Huaguang Wang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Ran Ni
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, 637459, Singapore
| | - Zexin Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
- Institute for Advanced Study, Center for Soft Condensed Matter Physics and Interdisciplinary Research, School of Physical Science and Technology, Soochow University, Suzhou, 215006, China
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2
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Zhang F, Yu H, Wang H, Zhang Z. Comparative study of the dynamics of colloidal glass and gel. J Chem Phys 2023; 158:2888843. [PMID: 37144714 DOI: 10.1063/5.0146692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/18/2023] [Indexed: 05/06/2023] Open
Abstract
We investigate and compare the difference in the dynamics of two arrested states: colloidal glass and colloidal gel. Real-space experiments reveal two distinct nonergodicity origins for their slow dynamics, namely, cage effects for the glass and attractive bondings for the gel. Such distinct origins lead to a faster decay of the correlation function and a smaller nonergodicity parameter of the glass than those of the gel. We also find that the gel exhibits stronger dynamical heterogeneity compared with the glass due to the greater correlated motions in the gel. Moreover, a logarithmic decay in the correlation function is observed as the two nonergodicity origins merge, consistent with the mode coupling theory.
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Affiliation(s)
- Fukai Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Haitao Yu
- The High School Affiliated to Southwest University, Chongqing 400700, China
| | - Huaguang Wang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Zexin Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
- Institute for Advanced Study, Center for Soft Condensed Matter Physics and Interdisciplinary Research, School of Physical Science and Technology, Soochow University, Suzhou 215006, China
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3
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Liu P, Ning L, Zong Y, Ye F, Yang M, Chen K. Lattice Induced Short-Range Attraction between Like-Charged Colloidal Particles. PHYSICAL REVIEW LETTERS 2022; 129:018002. [PMID: 35841542 DOI: 10.1103/physrevlett.129.018002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 04/13/2022] [Accepted: 06/02/2022] [Indexed: 06/15/2023]
Abstract
We perform experiments and computer simulations to study the effective interactions between like-charged colloidal tracers moving in a two-dimensional fluctuating background of colloidal crystal. By a counting method that properly accounts for the configurational degeneracy of tracer pairs, we extract the relative probability of finding a tracer pair in neighboring triangular cells formed by background particles. We find that this probability at the nearest neighbor cell is remarkably greater than those at cells with larger separations, implying an effective attraction between the tracers. This effective attraction weakens sharply as the background lattice constant increases. Furthermore, we clarify that the lattice-mediated effective attraction originates from the minimization of free energy increase from deformation of the crystalline background due to the presence of diffusing tracers.
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Affiliation(s)
- Peng Liu
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325001, China
| | - Luhui Ning
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325001, China
| | - Yiwu Zong
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Fangfu Ye
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325001, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Mingcheng Yang
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Ke Chen
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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4
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Kang N, Zhu J, Zhang X, Wang H, Zhang Z. Reconfiguring Self-Assembly of Photoresponsive Hybrid Colloids. J Am Chem Soc 2022; 144:4754-4758. [PMID: 35266712 DOI: 10.1021/jacs.2c00432] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reconfigurable self-assembly of colloidal particles allows the bottom-up creation of adaptive materials, yet significant challenges remain. Here, we demonstrate a synthesis of photoresponsive Fe2O3/polysiloxane hybrid colloids that perform a dynamically reconfigurable self-assembly. Such self-assembly is due to chemical gradients originating from the decomposition of H2O2 by the Fe2O3 component under UV irradiation. The morphology of the self-assembly includes chains and flower-structures, where the chains can be transformed in situ into flower-like structures with decreasing UV intensity. The flower-structures can be further switched by applying an external magnetic field, leading to orientationally ordered clusters. This, interestingly, leads to an asymmetrical chemical gradient surrounding the assemblies, and transforms the cluster into a micromotor exhibiting a self-propulsion steerable by the magnetic field. Our findings demonstrate a new possibility to control and reconfigure the self-assembly of colloids, which offers an important pathway for fabrications of adaptive and smart materials at the microscale.
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Affiliation(s)
- Ning Kang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Jiao Zhu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Xiaoliang Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Huaguang Wang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Zexin Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China.,Institute for Advanced Study, Center for Soft Condensed Matter Physics and Interdisciplinary Research, School of Physical Science and Technology, Soochow University, Suzhou 215006, China
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5
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Behjatian A, Walker-Gibbons R, Schekochihin AA, Krishnan M. Nonmonotonic Pair Potentials in the Interaction of Like-Charged Objects in Solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:786-800. [PMID: 34981941 DOI: 10.1021/acs.langmuir.1c02801] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We consider the long-standing like-charge attraction problem, wherein under certain conditions, similarly charged spheres suspended in aqueous electrolyte have been observed to display a minimum in their interaction potential, contrary to the intuitively expected monotonically varying repulsion. Recently, we described an interfacial mechanism invoking the molecular nature of the solvent that explains this anomalous experimental observation. In our model for the interaction of negatively charged particles in water, the minimum in the pair potential results from the superposition of competing contributions to the total free energy. One of these contributions is the canonical repulsive electrostatic term, whereas the other is a solvation-induced attractive contribution. We find that whereas both contributions grow approximately exponentially with decreasing interparticle separation, the occurrence of a stable, long-ranged minimum in the pair potential arises from differences in the precise interparticle separation dependence of the two terms. Specifically, the interfacial solvation term exhibits a more gradual decay with distance than the electrostatic repulsion, permitting the attractive contribution to dominate the interaction at large distances. Importantly, these disparities become evident in quantities calculated from exact numerical solutions to the governing nonlinear Poisson-Boltzmann (PB) equation for the spatial electrical potential distribution in the system. In marked contrast, we find that the linearized PB equation, applicable in the regime of low surface electrical potentials, does not support nonmonotonic trends in the total interaction free energy within the present model. Our results point to the importance of exact descriptions of electrostatic interactions in real systems that most often do not subscribe to particular mathematical limits where analytical approximations may provide a sufficiently accurate description of the problem.
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Affiliation(s)
- Ali Behjatian
- Physical & Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Rowan Walker-Gibbons
- Physical & Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Alexander A Schekochihin
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
- Merton College, Merton Street, Oxford OX1 4JD, United Kingdom
| | - Madhavi Krishnan
- Physical & Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
- Merton College, Merton Street, Oxford OX1 4JD, United Kingdom
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6
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Wu J, Li J, Liu X, Gong L, Chen J, Tang Z, Lin W, Mu Y, Lin X, Hong W, Yi G, Chen X. Unclonable Photonic Crystal Hydrogels with Controllable Encoding Capacity for Anticounterfeiting. ACS APPLIED MATERIALS & INTERFACES 2022; 14:2369-2380. [PMID: 34958565 DOI: 10.1021/acsami.1c20905] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Inspired by the formation of random sparkling microcrystallines in naturally precious opals, we develop a new strategy to produce a class of unclonable photonic crystal hydrogels (UPCHs) induced by the electrostatic interaction effect, which further achieve unclonable encoding/decoding and random high-encrypted patterns along with an ultrahigh and controllable encoding capacity up to ca. 2 × 10166055. Owing to the randomness of colloidal crystals in the self-assembly process, UPCHs with randomly distributed sparkling spots are endowed with unpredictable/unrepeatable characteristics. This, coupled with the water response of UPCHs with angle dependence and robustness, can upgrade the encryption level and address some limitations of easy fading, limited durability, and high cost in practical uses of existing unclonable materials. Interestingly, UPCHs can be readily patterned to exhibit reliable and rapid authentication by utilizing artificial intelligence (AI) deep learning, which can find broad applications in developing unbreakable and portable information storage/steganography systems not limited to anticounterfeiting.
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Affiliation(s)
- Jianyu Wu
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Jiawei Li
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Xiaochun Liu
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Li Gong
- Instrumental Analysis Research Center, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Jiayao Chen
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Zilun Tang
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Wenjing Lin
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Yingxiao Mu
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Xiaofeng Lin
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Wei Hong
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Guobin Yi
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Xudong Chen
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, P. R. China
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7
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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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8
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Flores-Tandy LM, García-Monjaraz AV, van Nierop EA, Vázquez-Martínez EA, Ruiz-Garcia J, Mejía-Rosales S. Fractal aggregates formed by ellipsoidal colloidal particles at the air/water interface. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.124477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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9
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Kubincová A, Hünenberger PH, Krishnan M. Interfacial solvation can explain attraction between like-charged objects in aqueous solution. J Chem Phys 2020; 152:104713. [PMID: 32171222 DOI: 10.1063/1.5141346] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Over the past few decades, the experimental literature has consistently reported observations of attraction between like-charged colloidal particles and macromolecules in aqueous solution. Examples include nucleic acids and colloidal particles in the bulk solution and under confinement, and biological liquid-liquid phase separation. This observation is at odds with the intuitive expectation of an interparticle repulsion that decays monotonically with distance. Although attraction between like-charged particles can be rationalized theoretically in the strong-coupling regime, e.g., in the presence of multivalent counterions, recurring accounts of long-range attraction in aqueous solution containing monovalent ions at low ionic strength have posed an open conundrum. Here, we show that the behavior of molecular water at an interface-traditionally disregarded in the continuum electrostatics picture-provides a mechanism to explain the attraction between like-charged objects in a broad spectrum of experiments. This basic principle will have important ramifications in the ongoing quest to better understand intermolecular interactions in solution.
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Affiliation(s)
- Alžbeta Kubincová
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Philippe H Hünenberger
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Madhavi Krishnan
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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10
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Li N, Zhang W, Jiang Z, Chen W. Spatial Cross-Correlated Diffusion of Colloids under Shear Flow. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:10537-10542. [PMID: 30117740 DOI: 10.1021/acs.langmuir.8b01803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The spatial cross-correlated diffusion of colloidal particles is often used as an essential tool to study the dynamic properties of a fluid because it directly describes the hydrodynamic interaction between two particles in a fluid. However, the experimental measurement of cross-correlated diffusion can be substantially modified by even a weak shear flow. In this work, the effect of a shear flow on spatial cross-correlated diffusion is demonstrated using experimental measurements that show a clear dependence on pair angles. An analytical solution is proposed to explain the experimental observations. A numerical simulation is performed to systemically demonstrate the influence of shear flow on spatial cross-correlated diffusion. The results of the experiment, theoretical analysis, and numerical simulation agree well with each other. Therefore, this research provides a sensitive experimental method to determine the weak shear flow in any quasi-two-dimensional fluid systems.
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Affiliation(s)
- Na Li
- State Key Laboratory of Surface Physics and Department of Physics , Fudan University , Shanghai 200438 , China
| | - Wei Zhang
- School of Physical Science and Technology , China University of Mining and Technology , Xuzhou 221116 , China
| | - Zehui Jiang
- Department of Physics , Harbin Institute of Technology , Harbin 150001 , China
| | - Wei Chen
- State Key Laboratory of Surface Physics and Department of Physics , Fudan University , Shanghai 200438 , China
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11
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In situ X-ray scattering observation of two-dimensional interfacial colloidal crystallization. Nat Commun 2018; 9:1335. [PMID: 29626195 PMCID: PMC5889402 DOI: 10.1038/s41467-018-03767-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/12/2018] [Indexed: 11/23/2022] Open
Abstract
Charged colloids at interfaces hold such a simple configuration that their interactions are supposed to be fully elucidated in the framework of classical electrostatics, yet the mysterious existence of attractive forces between these like-charged particles has puzzled the scientific community for decades. Here, we perform the in situ grazing-incidence small-angle X-ray scattering study of the dynamic self-assembling process of two-dimensional interfacial colloids. This approach allows simultaneous monitoring of the in-plane structure and ordering and the out-of-plane immersion depth variation. Upon compression, the system undergoes multiple metastable intermediate states before the stable hexagonal close-packed monolayer forms under van der Waals attraction. Remarkably, the immersion depth of colloidal particles is found to increase as the interparticle distance decreases. Numerical simulations demonstrate the interface around a colloid is deformed by the electrostatic force from its neighboring particles, which induces the long-range capillary attraction. Colloids adsorbed at fluid interfaces can self-assemble into crystal, but the detail remains largely unknown due to experimental challenges. Using in situ X-ray scattering, Wu et al. show that out-of-plane electrostatic force induces in-plane capillary attraction between like-charged particles.
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12
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Grunewald C, Schmudde M, Graf C, Risse T. Structural Characterization of Ordered, Non-Close-Packed Functionalized Silica Nanoparticles on Gold Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:7494-7502. [PMID: 28718292 DOI: 10.1021/acs.langmuir.7b01804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nanostructured surfaces play an important role in modern science and technology. In particular, ordered arrangements of nonclose-packed nanoparticles created by self-assembly offer a versatile route to prepare systems, which can be used in various applications such as sensing, plasmonic devices or antireflection coatings. Self-assembly based systems are particularly appealing as preparation is rather simple. The ability of nanoparticle systems to form nonclosed packed monolayers by self-assembly depends on the balance of various energetic contributions in particular the adsorption energy, the lateral barrier for diffusion and the repulsion between particles. Even for simple model systems such as the monodispersed silica particles adsorbed on a bare gold surface investigated here, none of these quantities is easy to determine experimentally. To this end, we will report on a detailed characterization of the adsorption in particular with respect to the structural properties of the above-mentioned model system. Based on experimental results obtained by using quartz crystal microbalance with dissipation monitoring (QCM-D) as well as scanning electron microscopy (SEM) it is possible to determine the electrostatic pair potential from the lateral arrangement of the nano particles in the limit of low coverage.
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Affiliation(s)
- Christian Grunewald
- Freie Universität Berlin, Institut für Chemie und Biochemie , Takustr. 3, 14195 Berlin, Germany
| | - Madlen Schmudde
- Freie Universität Berlin, Institut für Chemie und Biochemie , Takustr. 3, 14195 Berlin, Germany
| | - Christina Graf
- Freie Universität Berlin, Institut für Chemie und Biochemie , Takustr. 3, 14195 Berlin, Germany
| | - Thomas Risse
- Freie Universität Berlin, Institut für Chemie und Biochemie , Takustr. 3, 14195 Berlin, Germany
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13
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Igwe IE, Zong Y, Yang X, Ouyang Z, Chen K. Induced Attraction between Polystyrene Colloidal Particles in a Binary Mixture with PNIPAM Colloidal Microgels. J Phys Chem B 2017; 121:5391-5395. [PMID: 28467075 DOI: 10.1021/acs.jpcb.6b12999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We investigate the phase behaviors of binary mixtures of polystyrene (PS) hard-sphere and poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAM) soft-sphere colloidal particles as a function of temperature. As the temperature increases, apparent attractions arise between the PS particles, to the point of clustering at the highest temperature. This attractive force is found to be due to the change in pH caused by the acrylic acid co-polymerized with the temperature-sensitive PNIPAM particles, which in turn collapses the sterical stabilizing surface layers on the PS particles. Our experiments provide a new way to tune colloidal interactions with temperature for particles that are otherwise insensitive to temperature variations.
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Affiliation(s)
- Isaiah E Igwe
- Institute of Theoretical Physics, Chinese Academy of Sciences , Zhong Guan Cun East Street 55 #, P.O. Box 2735, Beijing 100190, P. R. China.,School of Physical Sciences, University of Chinese Academy of Sciences , 19A Yuquan Road, Shijingshan District, Beijing 100049, P. R. China
| | - Yiwu Zong
- Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese of Academy of Sciences , Beijing 100190, P. R. China
| | - Xiunan Yang
- Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese of Academy of Sciences , Beijing 100190, P. R. China
| | - Zhongcan Ouyang
- Institute of Theoretical Physics, Chinese Academy of Sciences , Zhong Guan Cun East Street 55 #, P.O. Box 2735, Beijing 100190, P. R. China
| | - Ke Chen
- Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese of Academy of Sciences , Beijing 100190, P. R. China
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14
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Photo-Crosslinkable Colloids: From Fluid Structure and Dynamics of Spheres to Suspensions of Ellipsoids. Gels 2016; 2:gels2040029. [PMID: 30674159 PMCID: PMC6318651 DOI: 10.3390/gels2040029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 11/03/2016] [Accepted: 11/07/2016] [Indexed: 11/16/2022] Open
Abstract
Recently-developed photo-crosslinkable PMMA (polymethylmethacrylate) colloidal spheres are a highly promising system for fundamental studies in colloidal physics and may have a wide range of future technological applications. We synthesize these colloids and characterize their size distribution. Their swelling in a density- and index- matching organic solvent system is demonstrated and we employ dynamic light scattering (DLS), as also the recently-developed confocal differential dynamic microscopy (ConDDM), to characterize the structure and the dynamics of a fluid bulk suspension of such colloids at different particle densities, detecting significant particle charging effects. We stretch these photo-crosslinkable spheres into ellipsoids. The fact that the ellipsoids are cross-linked allows them to be fluorescently stained, permitting a dense suspension of ellipsoids, a simple model of fluid matter, to be imaged by direct confocal microscopy.
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15
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Gratale MD, Ma X, Davidson ZS, Still T, Habdas P, Yodh AG. Vibrational properties of quasi-two-dimensional colloidal glasses with varying interparticle attraction. Phys Rev E 2016; 94:042606. [PMID: 27841543 DOI: 10.1103/physreve.94.042606] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Indexed: 06/06/2023]
Abstract
We measure the vibrational modes and particle dynamics of quasi-two-dimensional colloidal glasses as a function of interparticle interaction strength. The interparticle attractions are controlled via a temperature-tunable depletion interaction. Specifically, the interparticle attraction energy is increased gradually from a very small value (nearly hard-sphere) to moderate strength (∼4k_{B}T), and the variation of colloidal particle dynamics and vibrations are concurrently probed. The particle dynamics slow monotonically with increasing attraction strength, and the particle motions saturate for strengths greater than ∼2k_{B}T, i.e., as the system evolves from a nearly repulsive glass to an attractive glass. The shape of the phonon density of states is revealed to change with increasing attraction strength, and the number of low-frequency modes exhibits a crossover for glasses with weak compared to strong interparticle attraction at a threshold of ∼2k_{B}T. This variation in the properties of the low-frequency vibrational modes suggests a new means for distinguishing between repulsive and attractive glass states.
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Affiliation(s)
- Matthew D Gratale
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Xiaoguang Ma
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Complex Assemblies of Soft Matter, CNRS-Solvay-UPenn UMI 3254, Bristol, Pennsylvania 19007-3624, USA
| | - Zoey S Davidson
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Tim Still
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Piotr Habdas
- Department of Physics, Saint Joseph's University, Philadelphia, Pennsylvania 19131, USA
| | - A G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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16
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González-Mozuelos P. Effective electrostatic interactions among charged thermo-responsive microgels immersed in a simple electrolyte. J Chem Phys 2016; 144:054902. [DOI: 10.1063/1.4941324] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- P. González-Mozuelos
- Departamento de Física, Cinvestav del I. P. N., Av. Instituto Politécnico Nacional 2508, Mexico, Distrito Federal, C. P. 07360, Mexico
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17
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Jenkins IC, Crocker JC, Sinno T. Interaction potentials from arbitrary multi-particle trajectory data. SOFT MATTER 2015; 11:6948-6956. [PMID: 26235938 DOI: 10.1039/c5sm01233c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Understanding the complex physics of particle-based systems at the nanoscale and mesoscale increasingly relies on simulation methods, empowered by exponential advances in computing speed. A major impediment to progress lies in reliably obtaining the interaction potential functions that control system behavior - which are key inputs for any simulation approach - and which are often difficult or impossible to obtain directly using traditional experimental methods. Here, we present a straightforward methodology for generating pair potential functions from large multi-particle trajectory datasets, with no operational constraints regarding their state of equilibration, degree of damping or presence of hydrodynamic interactions. Using simulated datasets, we demonstrate that the method is highly robust against trajectory perturbations from Brownian motion and common errors introduced by particle tracking algorithms. Given the recent rapid pace of advancement in high-speed and three-dimensional microscopy and associated particle tracking algorithms, we anticipate a near future experimental regime where easily collected high-dimensional trajectory sets can be rapidly converted to the detailed interaction and hydrodynamic force fields required to replicate the system's physics in simulation.
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Affiliation(s)
- Ian C Jenkins
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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18
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Ghosh S, Mugele F, Duits MHG. Effects of shear and walls on the diffusion of colloids in microchannels. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:052305. [PMID: 26066175 DOI: 10.1103/physreve.91.052305] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Indexed: 06/04/2023]
Abstract
Colloidal suspensions flowing through microchannels were studied for the effects of both the shear flow and the proximity of walls on the particles' self-diffusion. Use of hydrostatic pressure to pump micron-sized silica spheres dispersed in water-glycerol mixture through poly(dimethylsiloxane) channels with a cross section of 30×24μm(2), allowed variation in the local Peclet number (Pe) from 0.01 to 50. To obtain the diffusion coefficients, image-time series from a confocal scanning laser microscope were analyzed with a method that, after finding particle trajectories, subtracts the instantaneous advective displacements and subsequently measures the slopes of the mean squared displacement in the flow (x) and shear (y) directions. For dilute suspensions, the thus obtained diffusion coefficients (D(x) and D(y)) are close to the free diffusion coefficient at all shear rates. In concentrated suspensions, a clear increase with the Peclet number (for Pe > 10) is found, that is stronger for D(x) than for D(y). This effect of shear-induced collisions is counteracted by the contribution of walls, which cause a strong local reduction in D(x) and D(y).
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Affiliation(s)
- S Ghosh
- Physics of Complex Fluids Group, Department of Science and Technology, MESA+ Institute, University of Twente, P. O. Box 217, 7500 AE Enschede, The Netherlands
| | - F Mugele
- Physics of Complex Fluids Group, Department of Science and Technology, MESA+ Institute, University of Twente, P. O. Box 217, 7500 AE Enschede, The Netherlands
| | - M H G Duits
- Physics of Complex Fluids Group, Department of Science and Technology, MESA+ Institute, University of Twente, P. O. Box 217, 7500 AE Enschede, The Netherlands
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19
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Zhou Z, Hollingsworth JV, Hong S, Wei G, Shi Y, Lu X, Cheng H, Han CC. Effects of particle softness on shear thickening of microgel suspensions. SOFT MATTER 2014; 10:6286-6293. [PMID: 25028061 DOI: 10.1039/c4sm01181c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A series of microgel particles composed of a polystyrene (PS) core and a thermo-sensitive poly(N-isopropylacrylamide) (PNIPAM) shell with different shell thicknesses were investigated to elucidate the effect of microgel softness on its shear thickening behavior. Since the softness of the microgels increases with decreasing temperature through the volume phase transition effect of PNIPAM shell, the measured softness parameter, n, which is derived from the Zwanzig-Mountain equation, was used to measure and describe the combined influences of temperature and shell thickness. Confocal microscopy is used to investigate the interaction potential between microgel particles with different softness parameters. According to the obtained results, the softness parameter can provide an estimate for the shear thickening behavior of microgel suspensions, at least semi-quantitatively.
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Affiliation(s)
- Zhi Zhou
- State Key Laboratory of Polymer Physics and Chemistry, Joint Laboratory of Polymer Science and Materials, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, CAS, Beijing 100190, China.
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20
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Chen YR, Lee CL. A cell-model study on counterion fluctuations in macroionic systems: effect of non-extensiveness in entropy. Phys Chem Chem Phys 2014; 16:297-303. [PMID: 24253489 DOI: 10.1039/c3cp53318b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rigorously speaking, entropy is slightly non-extensive, and this non-extensiveness, which characterizes the degree of fluctuations, can contribute to effective interactions between mesoscopic objects. In this paper, we consider a pair of macroions, each accompanied by 1000 counterions, and with a cell-model description we demonstrate that the slow variation of non-extensiveness in counterion entropy over macroionic distance leads to an effective long-range attraction between the macroions. With the aid of Monte Carlo simulation and a Bragg-Williams theory including counterion number fluctuations, we find the depth of attraction in free energy to be approximately 0.2k(B)T. The observation in our cell-model study provides an insight for further understanding of effective interactions in real macroionic systems.
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Affiliation(s)
- Yiing-Rei Chen
- Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan
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21
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González-Mozuelos P, Guerrero-García GI, Olvera de la Cruz M. An exact method to obtain effective electrostatic interactions from computer simulations: The case of effective charge amplification. J Chem Phys 2013; 139:064709. [DOI: 10.1063/1.4817776] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Domínguez-García P. Microrheological consequences of attractive colloid-colloid potentials in a two-dimensional Brownian fluid. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2012; 35:73. [PMID: 22898939 DOI: 10.1140/epje/i2012-12073-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 07/04/2012] [Accepted: 07/10/2012] [Indexed: 06/01/2023]
Abstract
By using microrheological methods commonly employed in videomicroscopy experiments, we study the rheology of a two-dimensional computational fluid formed by Brownian disks with the aim of exploring the influence of some effective colloid-colloid attractive interactions. The model of fluid is developed by Brownian dynamics simulations without hydrodynamical interactions, and it is characterized by calculating its equation of state from the pair distribution function. Micromechanical properties, relative and intrinsic viscosity and freezing are discussed. Then, we include attractive forces such a Asakura-Oosawa depletion force or an empiric expression proposed by Grier and Hal (GH) for an anomalous electrostatic potential observed in confined and charged colloids. By using both potentials, viscosity is clearly increased, but when the GH potential is included, viscoelastic gel state is reached for intermediate values of surface concentration. Finally, we analyse the influence of the attractive potentials in the breaking-up by thermal fluctuations of linear chains formed by 2D particles, finding that the GH potential reduces the characteristical time at which the disks can be considered as disaggregated. In this work, we employ an experimental-like methodology for the study of a Brownian hard-disk fluid, providing a very useful link with experimental procedures.
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Affiliation(s)
- P Domínguez-García
- Dep. Física de Materiales, Universidad Nacional de Educación a Distancia, Madrid, Spain.
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23
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Zhang Z, Yunker PJ, Habdas P, Yodh AG. Cooperative rearrangement regions and dynamical heterogeneities in colloidal glasses with attractive versus repulsive interactions. PHYSICAL REVIEW LETTERS 2011; 107:208303. [PMID: 22181781 DOI: 10.1103/physrevlett.107.208303] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Indexed: 05/31/2023]
Abstract
Water-lutidine mixtures permit the interparticle potentials of colloidal particles suspended therein to be tuned, in situ, from repulsive to attractive. We employ these systems to directly elucidate the effects of interparticle potential on glass dynamics in experimental samples composed of the same particles at the same packing fractions. Cooperative rearrangement regions (CRRs) and heterogeneous dynamics are observed in both types of glasses. Compared to repulsive glasses, the attractive glass dynamics are found to be heterogeneous over a wider range of time and length scales, and its CRRs involve more particles. Additionally, the CRRs are observed to be stringlike structures in repulsive glasses and compact structures in attractive glasses. Thus, the experiments demonstrate explicitly that glassy dynamics can depend on the sign of the interparticle interaction.
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Affiliation(s)
- Zexin Zhang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou, China.
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24
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25
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Padgett M, Di Leonardo R. Holographic optical tweezers and their relevance to lab on chip devices. LAB ON A CHIP 2011; 11:1196-205. [PMID: 21327211 DOI: 10.1039/c0lc00526f] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
During the last decade, optical tweezers have been transformed by the combined availability of spatial light modulators and the speed of low-cost computing to drive them. Holographic optical tweezers can trap and move many objects simultaneously and their compatibility with other optical techniques, particularly microscopy, means that they are highly appropriate to lab-on-chip systems to enable optical manipulation, actuation and sensing.
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Affiliation(s)
- Miles Padgett
- School of Physics and Astronomy, SUPA, University of Glasgow, Scotland.
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26
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Domínguez-García P, Pastor JM, Rubio MA. Aggregation and disaggregation dynamics of sedimented and charged superparamagnetic micro-particles in water suspension. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2011; 34:36. [PMID: 21479782 DOI: 10.1140/epje/i2011-11036-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Accepted: 03/07/2011] [Indexed: 05/30/2023]
Abstract
This article presents results on the aggregation and disaggregation kinetics on a 1 μm diameter charged superparamagnetic particles dispersed in water under a constant uniaxial magnetic field in experiments with salt (KCl) added to the suspension in order to observe the behaviour of the system when the electrical properties of the particles have been screened. These particles have an electric charge and are confined between two separated 100 μm thick quartz windows, and sediment near the charged bottom wall. The electrostatic interactions that take place in this experimental setup may affect the micro-structure and colloidal stability of the suspension and thus, the dynamics of aggregation and disaggregation.
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27
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Wang Z, Qi W, Peng Y, Alsayed AM, Chen Y, Tong P, Han Y. Two features at the two-dimensional freezing transitions. J Chem Phys 2011; 134:034506. [DOI: 10.1063/1.3545967] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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29
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30
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Peng Y, Wang ZR, Alsayed AM, Yodh AG, Han Y. Melting of multilayer colloidal crystals confined between two walls. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:011404. [PMID: 21405695 DOI: 10.1103/physreve.83.011404] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Indexed: 05/30/2023]
Abstract
Video microscopy is employed to study the melting behaviors of multilayer colloidal crystals composed of diameter-tunable microgel spheres confined between two walls. We systematically explore film thickness effects on the melting process and on the phase behaviors of single crystal and polycrystalline films. Thick films (>4 layers) are observed to melt heterogeneously, while thin films (≤4 layers) melt homogeneously, even for polycrystalline films. Grain-boundary melting dominates other types of melting processes in polycrystalline films thicker than 12 layers. The heterogeneous melting from dislocations is found to coexist with grain-boundary melting in films between 5- and 12-layers. In dislocation melting, liquid nucleates at dislocations and forms lakelike domains embedded in the larger crystalline matrix; the "lakes" are observed to diffuse, interact, merge with each other, and eventually merge with large strips of liquid melted from grain boundaries. Thin film melting is qualitatively different: thin films homogeneously melt by generating many small defects which need not nucleate at grain boundaries or dislocations. For three- and four-layer thin films, different layers are observed to have the same melting point, but surface layers melt faster than bulk layers. Within our resolution, two- to four-layer films appear to melt in one step, while monolayers melt in two steps with an intermediate hexatic phase.
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Affiliation(s)
- Y Peng
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
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31
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Al-Obaidi H, Nasseri B, Florence AT. Dynamics of microparticles inside lipid vesicles: movement in confined spaces. J Drug Target 2010; 18:821-30. [DOI: 10.3109/1061186x.2010.526228] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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32
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Lee CL, Ng SK. Studies on electrostatic interactions of colloidal particles in two dimensions: a modeling approach. J Chem Phys 2010; 133:084504. [PMID: 20815577 DOI: 10.1063/1.3474805] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We study the effective electrostatic interactions between a pair of charged colloidal particles without salt ions while the system is confined in two dimensions. In particular, we use a simplified model to elucidate the effects of rotational fluctuations in counterion distribution. The results exhibit effective colloidal attractions under appropriate conditions. Meanwhile, long-range repulsions persist over most of our studied cases. The repulsive forces arise from the fact that in two dimensions, the charged colloids cannot be perfectly screened by counterions, as the residual quadrupole moments contribute to the repulsions at longer range. By applying multiple expansions, we find that the attractive forces observed at short range are mainly contributed by electrostatic interactions among higher-order electric moments. We argue that the scenario for attractive interactions discussed in this work is applicable to systems of charged nanoparticles or colloidal solutions with macroions.
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Affiliation(s)
- Chi-Lun Lee
- Department of Physics and Institute of Biophysics, National Central University, Jhongli 32001, Taiwan.
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33
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Kong Y, Parthasarathy R. Different modulation mechanisms of attractive colloidal interactions by lipid and protein functionalization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:10541-10545. [PMID: 20394445 DOI: 10.1021/la1005538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The nature of attractive interactions observed between like-charged microparticles near a confining wall remains an outstanding puzzle in colloidal science. The shortage of experimental systems that provide tunable attractions contributes to the lack of progress in solving this mystery. We have recently shown that the functionalization of microspheres with lipid membranes allows simple control of interparticle interactions as a function of membrane composition (Kong, Y.; Parthasarathy, R. Soft Matter 2009, 5, 2027-2032). Here we introduce a new approach to biomembrane-mediated control in which varying amounts of a peripheral membrane protein, cholera toxin subunit B, are bound to the surface of lipid-functionalized silica particles. Protein functionalization again provides a family of tunable attractive pair interactions, measured using an optical line trap. Surprisingly, however, the form of interactions is strikingly different for particles with protein-plus-lipid membranes than for particles with lipid-only membranes, displaying opposite correlations between the depth of the attractive potential well and the spatial range of the interaction as well as between the well depth and the distance to the confining wall. Our findings and their distinctiveness from previous membrane-functionalized systems not only demonstrate an orthogonal route to the practical control of colloidal assembly but also, more fundamentally, show that multiple physical mechanisms or mechanisms that are especially sensitive to particle surface chemistries may be responsible for governing like-charge attraction in colloidal systems.
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Affiliation(s)
- Yupeng Kong
- Department of Physics and Materials Science Institute, The University of Oregon, Eugene, Oregon 97403-1274, USA
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34
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Peng Y, Wang Z, Alsayed AM, Yodh AG, Han Y. Melting of colloidal crystal films. PHYSICAL REVIEW LETTERS 2010; 104:205703. [PMID: 20867039 DOI: 10.1103/physrevlett.104.205703] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Revised: 03/26/2010] [Indexed: 05/29/2023]
Abstract
We study melting mechanisms in single and polycrystalline colloidal films composed of diameter-tunable microgel spheres with short-ranged repulsive interactions and confined between two glass walls. Thick films (>4 layers), thin-films (≤4 layers), and monolayers exhibit different melting behaviors. Thick films melt from grain boundaries in polycrystalline solid films and from film-wall interfaces in single-crystal films; a liquid-solid coexistence regime is observed in thick films but vanishes at a critical thickness of 4 layers. Thin solid films (2 to 4 layers) melt into the liquid phase in one step from both grain boundaries and from within crystalline domains. Monolayers melt in two steps with a middle hexatic phase.
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Affiliation(s)
- Y Peng
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
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35
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Arenas-Gómez BL, González-Mozuelos P. Charge renormalization of nanoparticles immersed in a molecular electrolyte. J Chem Phys 2010; 132:014903. [DOI: 10.1063/1.3285645] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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36
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Lee SH, Liddell CM. Anisotropic magnetic colloids: a strategy to form complex structures using nonspherical building blocks. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2009; 5:1957-62. [PMID: 19415647 DOI: 10.1002/smll.200900135] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
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37
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Domínguez-García P, Pastor JM, Melle S, Rubio MA. Electrostatic and hydrodynamics effects in a sedimented magnetorheological suspension. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:021405. [PMID: 19792122 DOI: 10.1103/physreve.80.021405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Indexed: 05/28/2023]
Abstract
We present experimental results on the equilibrium microstructure of a sedimented magnetorheological suspension, namely, an aqueous suspension of micron-sized superparamagnetic particles. We develop a study of the electrical interactions on the suspension by processing video-microscopy images of the sedimented particles. We calculate the pair distribution function, g(r), which yields the electrostatic pair potential u(r), showing an anomalous attractive interaction for distances on the order of twice the particle diameter, with characteristic parameters whose values show a dependence with the two-dimensional concentration of particles. The repulsive body of the potential is adjusted to a DLVO expression in order to calculate the Debye screening length and the effective surface charge density. Influence of confinement and variations on the Boltzmann sedimentation profile because of the electrostatic interactions appear to be essential for the interpretation of experimental results.
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Affiliation(s)
- P Domínguez-García
- Depto. Física de Materiales, UNED, Senda del Rey 9, 28040 Madrid, Spain.
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38
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Gomez EW, Clack NG, Wu HJ, Groves JT. Like-charge interactions between colloidal particles are asymmetric with respect to sign. SOFT MATTER 2009; 5:1931-1936. [PMID: 25221611 PMCID: PMC4161288 DOI: 10.1039/b821510c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Two-dimensional dispersions of colloidal particles with a range of surface chemistries and electrostatic potentials are characterized under a series of solution ionic strengths. A combination of optical imaging techniques are employed to monitor both the colloid structure and the electrostatic surface potential of individual particles in situ. We find that like-charge multiparticle interactions can be tuned from exclusively repulsive to long-range attractive by changing the particle surface composition. This behavior is strongly asymmetric with respect to the sign of the surface potential. Collective long-range attractive interactions are only observed among negatively charged particles.
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Affiliation(s)
- Esther W. Gomez
- Department of Chemical Engineering, University of California, Berkeley, CA, 94720, USA
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Nathan G. Clack
- Biophysics Graduate Group, University of California, Berkeley, CA, 94720, USA
| | - Hung-Jen Wu
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Jay T. Groves
- Biophysics Graduate Group, University of California, Berkeley, CA, 94720, USA
- Howard Hughes Medical Institute
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
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39
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Chen W, Tan S, Zhou Y, Ng TK, Ford WT, Tong P. Attraction between weakly charged silica spheres at a water-air interface induced by surface-charge heterogeneity. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:041403. [PMID: 19518229 DOI: 10.1103/physreve.79.041403] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2009] [Indexed: 05/27/2023]
Abstract
We report an optical and atomic force microscopic (AFM) study of interactions between weakly charged silica spheres at a water-air interface. Attractive interactions are observed at intermediate interparticle distances and the amplitude of the attraction increases with the amount of salt (NaCl) added into the water phase. AFM images obtained in the salty water show the formation of patchy charge domains of size approximately 100 nm on the silica surface. The experiment suggests that surface heterogeneity produced during ionization plays an important role in the generation of attractions between like-charged particles at the interface.
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Affiliation(s)
- Wei Chen
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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40
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Gyger M, Rückerl F, Käs J, Ruiz-García J. Errors in two particle tracking at close distances. J Colloid Interface Sci 2008; 326:382-6. [DOI: 10.1016/j.jcis.2008.06.046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Revised: 06/25/2008] [Accepted: 06/26/2008] [Indexed: 01/23/2023]
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41
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Polin M, Roichman Y, Grier DG. Autocalibrated colloidal interaction measurements with extended optical traps. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:051401. [PMID: 18643065 DOI: 10.1103/physreve.77.051401] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Revised: 02/22/2008] [Indexed: 05/26/2023]
Abstract
We describe an efficient technique for measuring the effective interaction potential for pairs of colloidal particles. The particles to be tested are confined in an extended optical trap, also known as a line tweezer, that is projected with the holographic optical trapping technique. Their diffusion along the line reflects not only their intrinsic interactions with each other, but also the influence of the line's potential energy landscape and interparticle interactions mediated by scattered light. We demonstrate that measurements of the particles' trajectories at just two laser powers can be used to correct explicitly for optically induced forces and that statistically optimal analysis for optically induced forces yields autocalibrated measurements of the particles' intrinsic interactions with remarkably few statistically independent measurements of the particles' separation.
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Affiliation(s)
- Marco Polin
- Department of Physics and Center for Soft Matter Research, New York University, New York, New York 10003, USA
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Han Y, Ha NY, Alsayed AM, Yodh AG. Melting of two-dimensional tunable-diameter colloidal crystals. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:041406. [PMID: 18517616 DOI: 10.1103/physreve.77.041406] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Revised: 11/24/2007] [Indexed: 05/26/2023]
Abstract
Melting of two-dimensional colloidal crystals is studied by video microscopy. The samples were composed of microgel spheres whose diameters could be temperature tuned, and whose pair potentials were measured to be short ranged and repulsive. We observed two-step melting from the crystal to a hexatic phase and from the hexatic to the liquid phase as a function of the temperature-tunable volume fraction. The translational and orientational susceptibilities enabled us to definitively determine the phase transition points, avoiding ambiguities inherent in other analyses and resolving a "dislocation precursor stage" in the solid phase that some of the traditional analyses may incorrectly associate with the hexatic phase. A prefreezing stage of the liquid with ordered patches was also found.
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Affiliation(s)
- Y Han
- Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6396, USA
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43
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Domínguez-García P, Melle S, Pastor JM, Rubio MA. Scaling in the aggregation dynamics of a magnetorheological fluid. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 76:051403. [PMID: 18233655 DOI: 10.1103/physreve.76.051403] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Indexed: 05/25/2023]
Abstract
We present experimental results on the aggregation dynamics of a magnetorheological fluid, namely, an aqueous suspension of micrometer-sized superparamagnetic particles, under the action of a constant uniaxial magnetic field using video microscopy and image analysis. We find a scaling behavior in several variables describing the aggregation kinetics. The data agree well with the Family-Vicsek scaling ansatz for diffusion-limited cluster-cluster aggregation. The kinetic exponents z and z' are obtained from the temporal evolution of the mean cluster size S(t) and the number of clusters N(t), respectively. The crossover exponent Delta is calculated in two ways: first, from the initial slope of the scaling function; second, from the evolution of the nonaggregated particles, n1(t). We report on results of Brownian two-dimensional dynamics simulations and compare the results with the experiments. Finally, we discuss the differences obtained between the kinetic exponents in terms of the variation in the crossover exponent and relate this behavior to the physical interpretation of the crossover exponent.
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Affiliation(s)
- P Domínguez-García
- Departamento Física Fundamental, Universidad Nacional de Educación a Distancisa, Senda del Rey 9, Madrid 28040, Spain.
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44
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Aguilar-Pineda GE, Jiménez-Angeles F, Yu J, Lozada-Cassou M. Van der Waals-Like Isotherms in a Confined Electrolyte by Spherical and Cylindrical Nanopores. J Phys Chem B 2007; 111:2033-44. [PMID: 17269816 DOI: 10.1021/jp066946y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electrolytes confined by spherical, cylindrical, and slit-like charged nanopores are studied. Results for ionic distribution profiles, pressures of the confined fluid, and absorption isotherms are obtained through the hypernetted chain/mean spherical approximation (HNC/MSA) integral equations theory. In spherical and cylindrical geometries, an inward, non-monotonic behavior of the pressure is found as confinement increases, implying a negative compressibility. The pressure vs volume isotherms resemble liquid-vapor van der Waals-like phase transition diagrams. This effect is correlated with a charge separation inside a spherical pore previously reported (Phys. Rev. Lett., 79, 3656, 1997). Here, the mechanism of charge separation and negative compressibility are explored in detail. When compared with the slit-like pore pressure, important qualitative differences are found.
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Affiliation(s)
- Gabriel E Aguilar-Pineda
- Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa Apartado Postal 55-534, 09340 México, D. F., México
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Abstract
When water-coated hydrophobic surfaces meet, direct contacts form between the surfaces, driving water out. However, long-range attractive forces first bring those surfaces close. This analysis reveals the source and strength of the long-range attraction between water-coated hydrophobic surfaces. The origin is in the polarization field produced by the strong correlation and coupling of the dipoles of the water molecules at the surfaces. We show that this polarization field gives rise to dipoles on the surface of the hydrophobic solutes that generate long-range hydrophobic attractions. Thus, hydrophobic aggregation begins with a step in which water-coated nonpolar solutes approach one another due to long-range electrostatic forces. This precursor regime occurs before the entropy increase of releasing the water layers and the short-range van der Waals attraction provide the driving force to "dry out" the contact surface. The effective force of attraction is derived from basic molecular principles, without assumptions of the structure of the hydrophobe-water interaction. The strength of this force can be measured directly from atomic force microscopy images of a hydrophobic molecule tethered to a surface but extending into water, and another hydrophobe attached to an atomic force probe. The phenomenon can be observed in the transverse relaxation rates in water proton magnetic resonance as well. The results shed light on the way water mediates chemical and biological self-assembly, a long outstanding problem.
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Affiliation(s)
- Florin Despa
- Pritzker School of Medicine, and Department of Chemistry, The University of Chicago, Chicago, Illinois, USA
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46
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Chen W, Tan S, Huang Z, Ng TK, Ford WT, Tong P. Measured long-ranged attractive interaction between charged polystyrene latex spheres at a water-air interface. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:021406. [PMID: 17025424 DOI: 10.1103/physreve.74.021406] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2006] [Revised: 07/11/2006] [Indexed: 05/12/2023]
Abstract
We report results of a systematic experimental study of interactions between charged polystyrene (PS) latex spheres at a water-air interface. Optical observations of stable bonded particle clusters and formation of circular chainlike structures at the interface demonstrate that the interaction potential is of dipole origin. Atomic force microscopy (AFM) is used to examine the distribution of charge groups on the colloidal surface. AFM phase images show patchy domains of size approximately 100 nm on the particle surface, indicating that the surface charge distribution of the PS spheres is not uniform, as is commonly believed. Such patchy charges can introduce fluctuating in-plane dipoles, leading to an attraction at short interparticle separations. A theoretical analysis is given to explain the mechanism for attractions between like-charged particles at the interface.
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Affiliation(s)
- Wei Chen
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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47
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Baumgartl J, Arauz-Lara JL, Bechinger C. Like-charge attraction in confinement: myth or truth? SOFT MATTER 2006; 2:631-635. [PMID: 32680220 DOI: 10.1039/b603052a] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
It is general wisdom that like-charged colloidal particles repel each other when suspended in liquids. This is in perfect agreement with mean field theories being developed more than 60 years ago. Accordingly, it was a big surprise when several groups independently reported long-ranged attractive components in the pair potential () of equally charged colloids. This so-called (LCA) was only observed in thin sample cells while the pair-interaction in unconfined suspensions has been experimentally confirmed to be entirely repulsive. Despite considerable experimental and theoretical efforts, LCA remains one of the most challenging mysteries in colloidal science. We experimentally reinvestigate the pair-potential () of charged colloidal particles with digital video microscopy and demonstrate that optical distortions in the particle's images lead to slightly erroneous particle positions. If not properly taken into account, this artefact pretends a minimum in () which was in the past misleadingly interpreted as LCA. After correcting optical distortions we obtain entirely repulsive pair interactions which show good agreement with linearized mean field theories.
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Affiliation(s)
- Jörg Baumgartl
- 2. Physikalisches Institut, Pfaffenwaldring 57, 70550, Stuttgart, Germany
| | - Jose Luis Arauz-Lara
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Alvaro Obregón 64, 78000, San Luis Potosí, Mexico
| | - Clemens Bechinger
- 2. Physikalisches Institut, Pfaffenwaldring 57, 70550, Stuttgart, Germany
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48
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Odriozola G, Jiménez-Angeles F, Lozada-Cassou M. Effect of confinement on the interaction between two like-charged rods. PHYSICAL REVIEW LETTERS 2006; 97:018102. [PMID: 16907411 DOI: 10.1103/physrevlett.97.018102] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Indexed: 05/11/2023]
Abstract
Monte Carlo simulations were employed to study two charged rods confined between two unlike charged plates, all immersed in a model electrolyte. Recently, it was shown that two rods immersed in a multivalent counterion solution may show attraction [Phys. Rev. Lett. 78, 2477 (1997)10.1103/PhysRevLett.78.2477]. Here we show for a monovalent electrolyte that rod-rod attraction and repulsion can switch sign depending on confinement and ionic size. We also propose a simple self-assembling mechanism which may be helpful to understand the DNA-lipid bilayers complexation.
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Affiliation(s)
- G Odriozola
- Programa de Ingeniería Molecular, Instituto Mexicano del Petróleo, Lázaro Cárdenas 152, 07730 Mexico, D. F., Mexico
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49
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Xiao C, Guo J, Hu P. Geometrical confinements and depletion interactions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:061403. [PMID: 16906823 DOI: 10.1103/physreve.73.061403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Revised: 03/23/2006] [Indexed: 05/11/2023]
Abstract
In the system with two large spheres confined between two parallel plates, there are depletion interactions between the two large spheres and between one large sphere and the closely placed plate. Obviously, the depletion interactions exerted on one large sphere will be strongly affected by the presence of the closely placed plate or the other large sphere. This prediction is confirmed by the numerical results obtained through the acceptance ratio method (ARM) or density integration method (DIM), i.e., they are strengthened when two large spheres are contacted. Furthermore, it is found that the influences on the depletion forces are also sensitive to the angle of the centers' connection line between the two large spheres and the confining walls. In addition, the numerical results show that the total depletion force exerted on one large sphere from both the other large sphere and the closely placed plate can be determined through ARM or DIM from the interactions between the two large spheres or between one large sphere and the corresponding closely placed plate.
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Affiliation(s)
- Changming Xiao
- Department of Physics, Hunan Normal University, 410081 China.
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50
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Chou CY, Payandeh B, Robert M. Colloid interaction and pair correlation function of one-dimensional colloid-polymer systems. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:041409. [PMID: 16711802 DOI: 10.1103/physreve.73.041409] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2005] [Revised: 03/01/2006] [Indexed: 05/09/2023]
Abstract
The interaction and pair correlation function of weakly charged colloidal particles in quasi-one-dimensional colloid-polymer systems are determined by enhanced video microscopy and digital image analysis. The pair correlation function is found to depend not only on the polymer concentration, but also on the degree of confinement; in particular, it depends on whether the channel width is such that mutual passage of the colloid particles is possible or not. These findings are compared with exact results on short-range order in linear continuous systems.
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Affiliation(s)
- C-Y Chou
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005, USA
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