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Rizvi MH, Wang R, Schubert J, Crumpler WD, Rossner C, Oldenburg AL, Fery A, Tracy JB. Magnetic Alignment for Plasmonic Control of Gold Nanorods Coated with Iron Oxide Nanoparticles. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2203366. [PMID: 35679599 DOI: 10.1002/adma.202203366] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/03/2022] [Indexed: 06/15/2023]
Abstract
Plasmonic nanoparticles that can be manipulated with magnetic fields are of interest for advanced optical applications, diagnostics, imaging, and therapy. Alignment of gold nanorods yields strong polarization-dependent extinction, and use of magnetic fields is appealing because they act through space and can be quickly switched. In this work, cationic polyethyleneimine-functionalized superparamagnetic Fe3 O4 nanoparticles (NPs) are deposited on the surface of anionic gold nanorods coated with bovine serum albumin. The magnetic gold nanorods (MagGNRs) obtained through mixing maintain the distinct optical properties of plasmonic gold nanorods that are minimally perturbed by the magnetic overcoating. Magnetic alignment of the MagGNRs arising from magnetic dipolar interactions on the anisotropic gold nanorod core is comprehensively characterized, including structural characterization and enhancement (suppression) of the longitudinal surface plasmon resonance and suppression (enhancement) of the transverse surface plasmon resonance for light polarized parallel (orthogonal) to the magnetic field. The MagGNRs can also be driven in rotating magnetic fields to rotate at frequencies of at least 17 Hz. For suitably large gold nanorods (148 nm long) and Fe3 O4 NPs (13.4 nm diameter), significant alignment is possible even in modest (<500 Oe) magnetic fields. An analytical model provides a unified understanding of the magnetic alignment of MagGNRs.
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Affiliation(s)
- Mehedi H Rizvi
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Ruosong Wang
- Leibniz-Institut für Polymerforschung Dresden e.V., Institute for Physical Chemistry and Polymer Physics, 01069, Dresden, Germany
| | - Jonas Schubert
- Leibniz-Institut für Polymerforschung Dresden e.V., Institute for Physical Chemistry and Polymer Physics, 01069, Dresden, Germany
| | - William D Crumpler
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Christian Rossner
- Leibniz-Institut für Polymerforschung Dresden e.V., Institute for Physical Chemistry and Polymer Physics, 01069, Dresden, Germany
- Dresden Center for Intelligent Materials (DCIM), Technische Universität Dresden, 01069, Dresden, Germany
| | - Amy L Oldenburg
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Andreas Fery
- Leibniz-Institut für Polymerforschung Dresden e.V., Institute for Physical Chemistry and Polymer Physics, 01069, Dresden, Germany
- Chair for Physical Chemistry of Polymeric Materials, Technische Universität Dresden, 01062, Dresden, Germany
| | - Joseph B Tracy
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA
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2
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Pal A, De Filippo CA, Ito T, Kamal MA, Petukhov AV, De Michele C, Schurtenberger P. Shape Matters in Magnetic-Field-Assisted Assembly of Prolate Colloids. ACS NANO 2022; 16:2558-2568. [PMID: 35138802 PMCID: PMC8867904 DOI: 10.1021/acsnano.1c09208] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
An anisotropic colloidal shape in combination with an externally tunable interaction potential results in a plethora of self-assembled structures with potential applications toward the fabrication of smart materials. Here we present our investigation on the influence of an external magnetic field on the self-assembly of hematite-silica core-shell prolate colloids for two aspect ratios ρ = 2.9 and 3.69. Our study shows a rather counterintuitive but interesting phenomenon, where prolate colloids self-assemble into oblate liquid crystalline (LC) phases. With increasing concentration, particles with smaller ρ reveal a sequence of LC phases involving para-nematic, nematic, smectic, and oriented glass phases. The occurrence of a smectic phase for colloidal ellipsoids has been neither predicted nor reported before. Quantitative shape analysis of the particles together with extensive computer simulations indicate that in addition to ρ, a subtle deviation from the ideal ellipsoidal shape dictates the formation of this unusual sequence of field-induced structures. Particles with ρ = 2.9 exhibit a hybrid shape containing features from both spherocylinders and ellipsoids, which make their self-assembly behavior richer than that observed for either of the "pure" shapes. The shape of the particles with higher ρ matches closely with the ideal ellipsoids, as a result their phase behavior follows the one expected for a "pure" ellipsoidal shape. Using anisotropic building blocks and external fields, our study demonstrates the ramifications of the subtle changes in the particle shape on the field-directed self-assembled structures with externally tunable properties.
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Affiliation(s)
- Antara Pal
- Division
of Physical Chemistry, Department of Chemistry, Lund University, Lund SE-22100, Sweden
| | - Carlo Andrea De Filippo
- Dipartimento
di Scienze, Università degli Studi
Roma Tre, Via della Vasca
Navale, 84, 00146 Rome, Italy
| | - Thiago Ito
- Division
of Physical Chemistry, Department of Chemistry, Lund University, Lund SE-22100, Sweden
| | - Md. Arif Kamal
- Centre
Interdisciplinaire de Nanoscience de Marseille (CINaM), CNRS, Aix Marseille University, Campus de Luminy − Case 913, 13288 CEDEX 09 Marseille, France
| | - Andrei V. Petukhov
- Van’t
Hoff Laboratory for Physical and Colloid Chemistry, Utrecht University, Utrecht 3584 CH, The Netherlands
- Laboratory
of Physical Chemistry, Eindhoven University
of Technology, Eindhoven 5600 MB, The Netherlands
| | | | - Peter Schurtenberger
- Division
of Physical Chemistry, Department of Chemistry, Lund University, Lund SE-22100, Sweden
- Lund Institute
of Advanced Neutron and X-ray Science LINXS, Lund University, Lund SE-22370, Sweden
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3
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Abstract
Colloidal self-assembly refers to a solution-processed assembly of nanometer-/micrometer-sized, well-dispersed particles into secondary structures, whose collective properties are controlled by not only nanoparticle property but also the superstructure symmetry, orientation, phase, and dimension. This combination of characteristics makes colloidal superstructures highly susceptible to remote stimuli or local environmental changes, representing a prominent platform for developing stimuli-responsive materials and smart devices. Chemists are achieving even more delicate control over their active responses to various practical stimuli, setting the stage ready for fully exploiting the potential of this unique set of materials. This review addresses the assembly of colloids into stimuli-responsive or smart nanostructured materials. We first delineate the colloidal self-assembly driven by forces of different length scales. A set of concepts and equations are outlined for controlling the colloidal crystal growth, appreciating the importance of particle connectivity in creating responsive superstructures. We then present working mechanisms and practical strategies for engineering smart colloidal assemblies. The concepts underpinning separation and connectivity control are systematically introduced, allowing active tuning and precise prediction of the colloidal crystal properties in response to external stimuli. Various exciting applications of these unique materials are summarized with a specific focus on the structure-property correlation in smart materials and functional devices. We conclude this review with a summary of existing challenges in colloidal self-assembly of smart materials and provide a perspective on their further advances to the next generation.
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Affiliation(s)
- Zhiwei Li
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Qingsong Fan
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Yadong Yin
- Department of Chemistry, University of California, Riverside, California 92521, United States
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4
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Lan T, Ding B, Huang Z, Bian F, Pan Y, Cheng HM, Liu B. Collective Behavior Induced Highly Sensitive Magneto-Optic Effect in 2D Inorganic Liquid Crystals. J Am Chem Soc 2021; 143:12886-12893. [PMID: 34369770 DOI: 10.1021/jacs.1c07481] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Collective behavior widely exists in nature, ranging from the macroscopic cloud of swallows to the microscopic cloud of colloidal particles. The behavior of an individual inside the collective is distinctive from its behavior alone, as it follows its neighbors. The introduction of such collective behavior in two-dimensional (2D) materials may offer new degrees of freedom to achieve desired but unattained properties. Here, we report a highly sensitive magneto-optic effect and transmissive magneto-coloration via introduction of collective behavior into magnetic 2D material dispersions. The increase of ionic strength in the dispersion enhances the collective behavior of colloidal particles, giving rise to a magneto-optic Cotton-Mouton coefficient up to 2700 T-2 m-1 which is the highest value obtained so far, being 3 orders of magnitude larger than other known transparent media. We also reveal linear dependence of magneto-coloration on the concentration and hydration ratios of ions. Such linear dependence and the extremely large Cotton-Mouton coefficient cooperatively allow fabrication of giant magneto-birefringent devices for color-centered visual sensing.
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Affiliation(s)
- Tianshu Lan
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Baofu Ding
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Ziyang Huang
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Fenggang Bian
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
| | - Yikun Pan
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Hui-Ming Cheng
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.,Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.,Advanced Technology Institute, University of Surrey, Guildford GU2 7XH, U.K
| | - Bilu Liu
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
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Goethite Nanorods: Synthesis and Investigation of the Size Effect on Their Orientation within a Magnetic Field by SAXS. NANOMATERIALS 2020; 10:nano10122526. [PMID: 33339200 PMCID: PMC7765628 DOI: 10.3390/nano10122526] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 12/11/2020] [Accepted: 12/12/2020] [Indexed: 11/16/2022]
Abstract
Goethite is a naturally anisotropic, antiferromagnetic iron oxide. Following its atomic structure, crystals grow into a fine needle shape that has interesting properties in a magnetic field. The needles align parallel to weak magnetic fields and perpendicular when subjected to high fields. We synthesized goethite nanorods with lengths between 200 nm and 650 nm in a two-step process. In a first step we synthesized precursor particles made of akaganeite (β-FeOOH) rods from iron(III)chloride. The precursors were then treated in a hydrothermal reactor under alkaline conditions with NaOH and polyvinylpyrrolidone (PVP) to form goethite needles. The aspect ratio was tunable between 8 and 15, based on the conditions during hydrothermal treatment. The orientation of these particles in a magnetic field was investigated by small angle X-ray scattering (SAXS). We observed that the field strength required to trigger a reorientation is dependent on the length and aspect ratio of the particles and could be shifted from 85 mT for the small particles to about 147 mT for the large particles. These particles could provide highly interesting magnetic properties to nanocomposites, that could then be used for sensing applications or membranes.
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6
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Kumar A, Joshi H, Kumar A. Remediation of Arsenic by Metal/ Metal Oxide Based Nanocomposites/ Nanohybrids: Contamination Scenario in Groundwater, Practical Challenges, and Future Perspectives. SEPARATION AND PURIFICATION REVIEWS 2020. [DOI: 10.1080/15422119.2020.1744649] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Ajay Kumar
- Department of Hydrology, Indian Institute of Technology Roorkee, Uttarakhand, India
| | - Himanshu Joshi
- Department of Hydrology, Indian Institute of Technology Roorkee, Uttarakhand, India
| | - Anil Kumar
- Department of Chemistry, Indian Institute of Technology Roorkee, Uttarakhand, India
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7
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Chaput F, Lerouge F, Bulin AL, Amans D, Odziomek M, Faure AC, Monteil M, Dozov I, Parola S, Bouquet F, Lecouvey M, Davidson P, Dujardin C. Liquid-Crystalline Suspensions of Photosensitive Paramagnetic CeF 3 Nanodiscs. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:16256-16265. [PMID: 31696717 DOI: 10.1021/acs.langmuir.9b02335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The design of high-performance energy-converting materials is an essential step for the development of sensors, but the production of the bulk materials currently used remains costly and difficult. Therefore, a different approach based on the self-assembly of nanoparticles has been explored. We report on the preparation by solvothermal synthesis of highly crystalline CeF3 nanodiscs. Their surface modification by bisphosphonate ligands led to stable, highly concentrated, colloidal suspensions in water. Despite the low aspect ratio of the nanodiscs (∼6), a liquid-crystalline nematic phase spontaneously appeared in these colloidal suspensions. Thanks to the paramagnetic character of the nanodiscs, the nematic phase was easily aligned by a weak (0.5 T) magnetic field, which provides a simple and convenient way of orienting all of the nanodiscs in suspension in the same direction. Moreover, the more dilute, isotropic, suspensions displayed strong (electric and magnetic) field-induced orientation of the nanodiscs (Kerr and Cotton-Mouton effects), with fast enough response times to make them suitable for use in electro-optic devices. Furthermore, an emission study showed a direct relation between the luminescence intensity and magnetic-field-induced orientation of the colloids. Finally, with their fast radiative recombination decay rates, the nanodiscs show luminescence properties that compare quite favorably with those of bulk CeF3. Therefore, these CeF3 nanodiscs are very promising building blocks for the development and processing of photosensitive materials for sensor applications.
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Affiliation(s)
- Frédéric Chaput
- Laboratoire de Chimie, CNRS UMR 5182 , Université Claude Bernard Lyon 1, Université de Lyon, Ens de Lyon , F69342 Lyon , France
| | - Frédéric Lerouge
- Laboratoire de Chimie, CNRS UMR 5182 , Université Claude Bernard Lyon 1, Université de Lyon, Ens de Lyon , F69342 Lyon , France
| | - Anne-Laure Bulin
- CNRS UMR 5306, Institut Lumière Matière , Univ Lyon, Université Claude Bernard Lyon 1 , F-69622 Villeurbanne , France
| | - David Amans
- CNRS UMR 5306, Institut Lumière Matière , Univ Lyon, Université Claude Bernard Lyon 1 , F-69622 Villeurbanne , France
| | - Mateusz Odziomek
- Laboratoire de Chimie, CNRS UMR 5182 , Université Claude Bernard Lyon 1, Université de Lyon, Ens de Lyon , F69342 Lyon , France
| | - Anne-Charlotte Faure
- Laboratoire de Chimie, CNRS UMR 5182 , Université Claude Bernard Lyon 1, Université de Lyon, Ens de Lyon , F69342 Lyon , France
| | - Maelle Monteil
- Laboratoire CSPBAT, UMR 7244, CNRS , Université Paris 13 , 74 Rue Marcel Cachin , 93017 Bobigny , France
| | - Ivan Dozov
- Laboratoire de Physique des Solides, CNRS , Univ. Paris-Sud, Université Paris-Saclay , 91405 Orsay Cedex, France
| | - Stéphane Parola
- Laboratoire de Chimie, CNRS UMR 5182 , Université Claude Bernard Lyon 1, Université de Lyon, Ens de Lyon , F69342 Lyon , France
| | - Frédéric Bouquet
- Laboratoire de Physique des Solides, CNRS , Univ. Paris-Sud, Université Paris-Saclay , 91405 Orsay Cedex, France
| | - Marc Lecouvey
- Laboratoire CSPBAT, UMR 7244, CNRS , Université Paris 13 , 74 Rue Marcel Cachin , 93017 Bobigny , France
| | - Patrick Davidson
- Laboratoire de Physique des Solides, CNRS , Univ. Paris-Sud, Université Paris-Saclay , 91405 Orsay Cedex, France
| | - Christophe Dujardin
- CNRS UMR 5306, Institut Lumière Matière , Univ Lyon, Université Claude Bernard Lyon 1 , F-69622 Villeurbanne , France
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8
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Chiappini M, Drwenski T, van Roij R, Dijkstra M. Biaxial, Twist-bend, and Splay-bend Nematic Phases of Banana-shaped Particles Revealed by Lifting the "Smectic Blanket". PHYSICAL REVIEW LETTERS 2019; 123:068001. [PMID: 31491177 DOI: 10.1103/physrevlett.123.068001] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 06/20/2019] [Indexed: 06/10/2023]
Abstract
We perform an extensive computational study on the phase behavior of hard banana-shaped particles, and show that biaxial, twist-bend, and splay-bend nematic phases are metastable with respect to a smectic phase for a system of hard bent spherocylinders. However, if the smectic phase is destabilized-either by polydispersity in the particle length or by curvature in the particle shape-stable biaxial, twist-bend, and splay-bend nematic phases are obtained. This provides a unified and consistent picture on the subtle role of particle shape on the phase behavior of bent rods.
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Affiliation(s)
- Massimiliano Chiappini
- Soft Condensed Matter, Debye Institute for Nanomaterials Science, Department of Physics, Utrecht University, Princetonplein 1, Utrecht 3584 CC, The Netherlands
| | - Tara Drwenski
- Institute for Theoretical Physics, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - René van Roij
- Institute for Theoretical Physics, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Marjolein Dijkstra
- Soft Condensed Matter, Debye Institute for Nanomaterials Science, Department of Physics, Utrecht University, Princetonplein 1, Utrecht 3584 CC, The Netherlands
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9
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Kurta RP, Wiegart L, Fluerasu A, Madsen A. Fluctuation X-ray scattering from nanorods in solution reveals weak temperature-dependent orientational ordering. IUCRJ 2019; 6:635-648. [PMID: 31316808 PMCID: PMC6608627 DOI: 10.1107/s2052252519005499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 04/23/2019] [Indexed: 06/10/2023]
Abstract
Higher-order statistical analysis of X-ray scattering from dilute solutions of polydisperse goethite nanorods was performed and revealed structural information which is inaccessible by conventional small-angle scattering. For instance, a pronounced temperature dependence of the correlated scattering from suspension was observed. The higher-order scattering terms deviate from those expected for a perfectly isotropic distribution of particle orientations, demonstrating that the method can reveal faint orientational order in apparently disordered systems. The observation of correlated scattering from polydisperse particle solutions is also encouraging for future free-electron laser experiments aimed at extracting high-resolution structural information from systems with low particle heterogeneity.
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Affiliation(s)
| | - Lutz Wiegart
- Brookhaven National Laboratory, Photon Sciences Directorate, Upton, NY 11973, USA
| | - Andrei Fluerasu
- Brookhaven National Laboratory, Photon Sciences Directorate, Upton, NY 11973, USA
| | - Anders Madsen
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
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10
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Wang D, Xu H, Ma J, Giannakis S, Lu X, Chi H, Song S, Qi J. Enhanced mineralization of atrazine by surface induced hydroxyl radicals over light-weight granular mixed-quartz sands with ozone. WATER RESEARCH 2019; 149:136-148. [PMID: 30439577 DOI: 10.1016/j.watres.2018.11.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/28/2018] [Accepted: 11/01/2018] [Indexed: 06/09/2023]
Abstract
A light-weight granular mixed-quartz sand (denoted as L-GQS) combined with stirring-assisted bubble column reactor was firstly applied in catalytic ozonation of atrazine. The L-GQS, with a density of 2.36 g cm-3 and average diameter of ca. of 4 mm, was readily churned up and uniformly distributed within the solution in the reactor. The introduction of L-GQS was found to exhibit enhanced catalytic ozonation of atrazine, with the increase in degradation rate and the dissolved organic carbon (DOC) removal being more than 2-fold for the catalytic process (L-GQS dosage = 5 g L-1, [atrazine]0 = 50 μM, [O3] = 25 mg L-1, gas flow = 0.2 L min-1, at pH 7.0 and 293 K). The L-GQS settled at the bottom of the reactor after experimentation, allowing its easy separation from the solution. A complete characterization of the material (XRD, XPS, FTIR, FE-SEM/EDS, BET and pHpzc) revealed that L-GQS consisted of α-quartz, β-cristobalite, anorthoclase and small amount of iron oxy-hydroxides. Hydroxyl groups, Bronsted acid sites and Lewis acid sites on the surface of L-GQS all contributed to the atrazine adsorption, ozone decomposition and ·OH generation. The L-GQS catalyzed ozonation exhibited superior atrazine degradation and mineralization rates in a wide range of pH (3.0-9.0) and reaction temperatures (278 K-293 K). Also, an enhancement of DOC abatement was observed both in presence of natural organic matter isolates and natural water matrices (river water) when L-GQS was used. Finally, the degradation mechanism was proposed, based on the intermediates and by-products formation analyzed by LC-QTOF-MS/MS and ionic chromatography. Our results indicate that the L-GQS combined with stirring-assisted bubble column reactor could be utilized as an enhancement of ozone-based advanced oxidation processes.
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Affiliation(s)
- Da Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China; School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École polytechnique fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland
| | - Haodan Xu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
| | - Stefanos Giannakis
- School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École polytechnique fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland
| | - Xiaohui Lu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Huizhong Chi
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Shuang Song
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China
| | - Jingyao Qi
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
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11
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Pan H, Chen Z, Zhu S, Jiang C, Zhang D. Photoelastic colloidal gel for a high-sensitivity strain sensor. NANOTECHNOLOGY 2018; 29:175502. [PMID: 29446759 DOI: 10.1088/1361-6528/aaafac] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Nanoparticles, having the ability to self-assemble into an ordered structure in their suspensions, analogous to liquid crystals, have attracted extensive attention. Herein, we report a new type of colloidal gel with an ordered crystal structure assembled from 1D and 2D nanoparticles. The material has high elasticity and, more interestingly, it shows significant photoelasticity. Its refractive index can be tuned under external stress and exhibits an ultra-wide dynamic range (Δn) of the order of 10-2. Due to the large Δn, the material shows an extremely high strain sensibility of 720 nm/ε, an order of magnitude higher than the reported ones.
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Affiliation(s)
- Hui Pan
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
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12
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Nack A, Seifert J, Passow C, Wagner J. Hindered nematic alignment of hematite spindles in poly(N-isopropylacrylamide) hydrogels: a small-angle X-ray scattering and rheology study. J Appl Crystallogr 2018. [DOI: 10.1107/s1600576717017411] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Field-induced changes to the mesostructure of ferrogels consisting of spindle-shaped hematite particles and poly(N-isopropylacrylamide) are investigated by means of small-angle X-ray scattering (SAXS). Related field-induced changes to the macroscopic viscoelastic properties of these composites are probed by means of oscillatory shear experiments in an external magnetic field. Because of their magnetic moment and magnetic anisotropy, the hematite spindles align with their long axis perpendicular to the direction of an external magnetic field. The field-induced torque acting on the magnetic particles leads to an elastic deformation of the hydrogel matrix. Thus, the field-dependent orientational distribution functions of anisotropic particles acting as microrheological probes depend on the elastic modulus of the hydrogel matrix. The orientational distribution functions are determined by means of SAXS experiments as a function of the varying flux density of an external magnetic field. With increasing elasticity of the hydrogels, tunedviathe polymer volume fraction and the crosslinking density, the field-induced alignment of these anisotropic magnetic particles is progressively hindered. The microrheological results are in accordance with macrorheological experiments indicating increasing elasticity with increasing flux density of an external field.
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13
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Celebre G, D'Urso C, Porto M. Extensive molecular field theoretical investigation of thermotropic biaxial nematics composed of board-like (D) molecules in the partially repulsive regime of orientational interactions. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.10.093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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14
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Coursault D, Dozov I, Blanc C, Nobili M, Dupont L, Chanéac C, Davidson P. Dispersions of Goethite Nanorods in Aprotic Polar Solvents. MATERIALS 2017; 10:ma10101191. [PMID: 29039797 PMCID: PMC5666997 DOI: 10.3390/ma10101191] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 10/12/2017] [Accepted: 10/14/2017] [Indexed: 11/16/2022]
Abstract
Colloidal suspensions of anisotropic nanoparticles can spontaneously self-organize in liquid-crystalline phases beyond some concentration threshold. These phases often respond to electric and magnetic fields. At lower concentrations, usual isotropic liquids are observed but they can display very strong Kerr and Cotton-Mouton effects (i.e., field-induced particle orientation). For many examples of these colloidal suspensions, the solvent is water, which hinders most electro-optic applications. Here, for goethite (α-FeOOH) nanorod dispersions, we show that water can be replaced by polar aprotic solvents, such as N-methyl-2-pyrrolidone (NMP) and dimethylsulfoxide (DMSO), without loss of colloidal stability. By polarized-light microscopy, small-angle X-ray scattering and electro-optic measurements, we found that the nematic phase, with its field-response properties, is retained. Moreover, a strong Kerr effect was also observed with isotropic goethite suspensions in these polar aprotic solvents. Furthermore, we found no significant difference in the behavior of both the nematic and isotropic phases between the aqueous and non-aqueous dispersions. Our work shows that goethite nanorod suspensions in polar aprotic solvents, suitable for electro-optic applications, can easily be produced and that they keep all their outstanding properties. It also suggests that this solvent replacement method could be extended to the aqueous colloidal suspensions of other kinds of charged anisotropic nanoparticles.
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Affiliation(s)
- Delphine Coursault
- Laboratoire Charles Coulomb, CNRS, Université de Montpellier, 34095 Montpellier, France.
| | - Ivan Dozov
- Laboratoire Charles Coulomb, CNRS, Université de Montpellier, 34095 Montpellier, France.
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France.
| | - Christophe Blanc
- Laboratoire Charles Coulomb, CNRS, Université de Montpellier, 34095 Montpellier, France.
| | - Maurizio Nobili
- Laboratoire Charles Coulomb, CNRS, Université de Montpellier, 34095 Montpellier, France.
| | - Laurent Dupont
- IMT Atlantique, Optics Department, Technopôle Brest-Iroise, CS 83818, 29238 Brest Cedex 3, France.
| | - Corinne Chanéac
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, 4 place Jussieu, 75005 Paris, France.
| | - Patrick Davidson
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France.
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15
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Sonin AS, Churochkina NA, Kaznacheev AV, Golovanov AV. Mineral liquid crystals. COLLOID JOURNAL 2017. [DOI: 10.1134/s1061933x17040159] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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16
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Agresti F, Zin V, Barison S, Sani E, Meucci M, Mercatelli L, Nodari L, Rossi S, Bobbo S, Fabrizio M. NIR transmittance tuneability under a magnetic field of colloidal suspensions of goethite (α-FeOOH) nanorods. RSC Adv 2017. [DOI: 10.1039/c7ra00721c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Goethite (α-FeOOH) nanorods were synthesized and their size and shape were controlled by synthesis parameters. Stable colloidal suspensions were prepared and their transmittance in NIR range was tuned by modifying magnetic field direction and strength.
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Affiliation(s)
- F. Agresti
- Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE)
- National Research Council of Italy (CNR)
- 35127 Padova
- Italy
| | - V. Zin
- Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE)
- National Research Council of Italy (CNR)
- 35127 Padova
- Italy
| | - S. Barison
- Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE)
- National Research Council of Italy (CNR)
- 35127 Padova
- Italy
| | - E. Sani
- National Institute of Optics (INO)
- National Research Council of Italy (CNR)
- 50125 Firenze
- Italy
| | - M. Meucci
- National Institute of Optics (INO)
- National Research Council of Italy (CNR)
- 50125 Firenze
- Italy
| | - L. Mercatelli
- National Institute of Optics (INO)
- National Research Council of Italy (CNR)
- 50125 Firenze
- Italy
| | - L. Nodari
- Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE)
- National Research Council of Italy (CNR)
- 35127 Padova
- Italy
| | - S. Rossi
- Institute of Construction Technologies (ITC)
- National Research Council of Italy (CNR)
- 35127 Padova
- Italy
| | - S. Bobbo
- Institute of Construction Technologies (ITC)
- National Research Council of Italy (CNR)
- 35127 Padova
- Italy
| | - M. Fabrizio
- Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE)
- National Research Council of Italy (CNR)
- 35127 Padova
- Italy
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17
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van der Asdonk P, Kouwer PHJ. Liquid crystal templating as an approach to spatially and temporally organise soft matter. Chem Soc Rev 2017; 46:5935-5949. [DOI: 10.1039/c7cs00029d] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Liquid crystal templating: an emerging technique to organise and control soft matter at multiple length scales.
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Affiliation(s)
- Pim van der Asdonk
- Radboud University
- Institute for Molecules and Materials
- 6525 AJ Nijmegen
- The Netherlands
| | - Paul H. J. Kouwer
- Radboud University
- Institute for Molecules and Materials
- 6525 AJ Nijmegen
- The Netherlands
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18
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Srikantharajah R, Schindler T, Landwehr I, Romeis S, Unruh T, Peukert W. From evaporation-induced self-assembly to shear-induced alignment. NANOSCALE 2016; 8:19882-19893. [PMID: 27878180 DOI: 10.1039/c6nr06586d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The functionality of compact nanostructured thin films depends critically on the degree of order and hence on the underlying ordering mechanisms during film formation. For dip coating of rigid nanorods the counteracting mechanisms, evaporation-induced self-assembly (EISA) and shear-induced alignment (SIA) have recently been identified as competing ordering mechanisms. Here, we show how to achieve highly ordered and homogeneous thin films by controlling EISA and SIA in dip coating. Therefore we identify the influences of the process parameters including temperature, initial volume fraction and nanorod aspect ratio on evaporation-induced convective flow and externally applied shear forces and evaluate the resulting films. The impact of evaporation and shear can be distinguished by analysing film thickness, surface order and bulk order by careful in situ SAXS, Raman and SEM-based image analysis. For the first time we derive processing guidelines for the controlled application of EISA and SIA towards highly ordered thin nematic films.
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Affiliation(s)
- R Srikantharajah
- Institute of Particle Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstraße 4, 91058 Erlangen, Germany.
| | - T Schindler
- Chair for Crystallography and Structural Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstraße 3, 91058 Erlangen, Germany
| | - I Landwehr
- Fraunhofer Institute for Manufacturing Engineering and Automation IPA, Nobelstraße 12, 70569 Stuttgart, Germany
| | - S Romeis
- Institute of Particle Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstraße 4, 91058 Erlangen, Germany.
| | - T Unruh
- Chair for Crystallography and Structural Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstraße 3, 91058 Erlangen, Germany
| | - W Peukert
- Institute of Particle Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstraße 4, 91058 Erlangen, Germany.
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19
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van der Asdonk P, Kragt S, Kouwer PHJ. Directing Soft Matter in Water Using Electric Fields. ACS APPLIED MATERIALS & INTERFACES 2016; 8:16303-16309. [PMID: 27269124 DOI: 10.1021/acsami.6b03910] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Directing the spatial organization of functional supramolecular and polymeric materials at larger length scales is essential for many biological and molecular optoelectronic applications. Although the application of electrical fields is one of the most powerful approaches to induce spatial control, it is rarely applied experimentally in aqueous solutions, since the low susceptibility of soft and biological materials requires the use of high fields, which leads to parasitic heating and electrochemical degradation. In this work, we demonstrate that we can apply electric fields when we use a mineral liquid crystal as a responsive template. Besides aligning and positioning functional soft matter, we show that the concentration of the liquid crystal template controls the morphology of the assembly. As our setup is very easy to operate and our approach lacks specific molecular interactions, we believe it will be applicable for a wide range of (aqueous) materials.
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Affiliation(s)
- Pim van der Asdonk
- Department of Molecular Materials, Institute for Molecules and Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Stijn Kragt
- Department of Molecular Materials, Institute for Molecules and Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Paul H J Kouwer
- Department of Molecular Materials, Institute for Molecules and Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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20
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Eremin A, Geng Y, Stannarius R, Ostapenko T, Challa PK, Gleeson JT, Jákli A, Klein S. Peculiarities of the magneto-optical response in dispersions of anisometric pigment nano-particles. RSC Adv 2016. [DOI: 10.1039/c6ra12020b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We demonstrate an unusually strong magneto-optical response of elongated plate-shaped pigment particles in magnetic fields ranging from 0 to 25 T.
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Affiliation(s)
- A. Eremin
- Otto-von-Guericke-Universität Magdeburg
- FNW/IEP/ANP
- 39016 Magdeburg
- Germany
| | - Y. Geng
- Otto-von-Guericke-Universität Magdeburg
- FNW/IEP/ANP
- 39016 Magdeburg
- Germany
| | - R. Stannarius
- Otto-von-Guericke-Universität Magdeburg
- FNW/IEP/ANP
- 39016 Magdeburg
- Germany
| | - T. Ostapenko
- Max Planck Institute for Dynamics and Self-Organization (MPIDS)
- 37077 Göttingen
- Germany
| | - P. K. Challa
- Department of Physics
- Kent State University
- Kent
- USA
| | | | - A. Jákli
- Liquid Crystal Institute
- Kent State University
- Kent
- USA
| | - S. Klein
- HP Laboratories
- Bristol BS34 8QZ
- UK
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21
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Frka-Petesic B, Sugiyama J, Kimura S, Chanzy H, Maret G. Negative Diamagnetic Anisotropy and Birefringence of Cellulose Nanocrystals. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b02201] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bruno Frka-Petesic
- Centre
de Recherches sur les Macromolécules Végétales
(CERMAV-CNRS), Université Grenoble Alpes, F-38000 Grenoble, France
| | - Junji Sugiyama
- Research
Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji,
Kyoto 611-0011 Japan
| | - Satoshi Kimura
- Department
of Biomaterials Science, Graduate School of Agricultural and Life
Sciences, The University of Tokyo, Tokyo 112-8657, Japan
| | - Henri Chanzy
- Centre
de Recherches sur les Macromolécules Végétales
(CERMAV-CNRS), Université Grenoble Alpes, F-38000 Grenoble, France
| | - Georg Maret
- Department
of Physics, University of Konstanz, D-78457 Konstanz, Germany
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22
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Passow C, ten Hagen B, Löwen H, Wagner J. Depolarized light scattering from prolate anisotropic particles: The influence of the particle shape on the field autocorrelation function. J Chem Phys 2015; 143:044903. [DOI: 10.1063/1.4926931] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
| | - Borge ten Hagen
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, D-40225 Düsseldorf, Germany
| | - Hartmut Löwen
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, D-40225 Düsseldorf, Germany
| | - Joachim Wagner
- Institut für Chemie, Universität Rostock, D-18051 Rostock, Germany
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23
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SAXS reveals the magnetic alignment pathway of the goethite columnar liquid crystal phase. J Colloid Interface Sci 2014; 428:316-20. [DOI: 10.1016/j.jcis.2014.04.061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/27/2014] [Accepted: 04/28/2014] [Indexed: 11/18/2022]
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24
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Wang M, He L, Zorba S, Yin Y. Magnetically actuated liquid crystals. NANO LETTERS 2014; 14:3966-3971. [PMID: 24914876 DOI: 10.1021/nl501302s] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Ferrimagnetic inorganic nanorods have been used as building blocks to construct liquid crystals with optical properties that can be instantly and reversibly controlled by manipulating the nanorod orientation using considerably weak external magnetic fields (1 mT). Under an alternating magnetic field, they exhibit an optical switching frequency above 100 Hz, which is comparable to the performance of commercial liquid crystals based on electrical switching. By combining magnetic alignment and lithography processes, it is also possible to create patterns of different polarizations in a thin composite film and control over the transmittance of light in particular areas. Developing such magnetically responsive liquid crystals opens the door toward various applications, which may benefit from the instantaneous and contactless nature of magnetic manipulation.
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Affiliation(s)
- Mingsheng Wang
- Department of Chemistry, University of California , Riverside, California 92521, United States
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25
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Slyusarenko K, Constantin D, Davidson P. A two-dimensional nematic phase of magnetic nanorods. J Chem Phys 2014; 140:104904. [DOI: 10.1063/1.4867790] [Citation(s) in RCA: 20] [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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26
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Perineau F, Rosticher C, Rozes L, Chanéac C, Sanchez C, Constantin D, Dozov I, Davidson P, Rochas C. Hybrid nanocomposites with tunable alignment of the magnetic nanorod filler. ACS APPLIED MATERIALS & INTERFACES 2014; 6:1583-1588. [PMID: 24428247 DOI: 10.1021/am404313s] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
For many important applications, the performance of polymer-anisotropic particle nanocomposite materials strongly depends on the orientation of the nanoparticles. Using the very peculiar magnetic properties of goethite (α-FeOOH) nanorods, we produced goethite-poly(hydroxyethyl methacrylate) nanocomposites in which the alignment direction and the level of orientation of the nanorods could easily be tuned by simply adjusting the intensity of a magnetic field applied during polymerization. Because the particle volume fraction was kept low (1-5.5 vol %), we used the orientational order induced by the field in the isotropic phase rather than the spontaneous orientational order of the nematic phase. At the strongest field values (up to 1.5 T), the particles exhibit almost perfect antinematic alignment, as measured by optical birefringence and small-angle X-ray scattering. The results of these two techniques are in remarkably good agreement, validating the use of birefringence measurements for quantifying the degree of orientational order. We also demonstrate that the ordering induced by the field in the isotropic suspension is preserved in the final material after field removal. This work illustrates the interest, for such problems, of considering the field-induced alignment of anisotropic nanoparticles in the isotropic phase, an approach that is effective at low filler content, that avoids the need of controlling the nematic texture, and that allows tuning of the orientation level of the particles at will simply by adjusting the field intensity.
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Affiliation(s)
- Fabien Perineau
- Sorbonne Universités, UPMC Université Paris 06, ‡CNRS, and §Collège de France, UMR 7574, Laboratoire de Chimie de la Matière Condensée de Paris, F-75005 Paris, France
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27
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Leferink op Reinink ABGM, Belli S, van Roij R, Dijkstra M, Petukhov AV, Vroege GJ. Tuning biaxiality of nematic phases of board-like colloids by an external magnetic field. SOFT MATTER 2014; 10:446-456. [PMID: 24652631 DOI: 10.1039/c3sm52242c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We study the influence of a magnetic field on the biaxial nematic phase of board-like goethite colloids both experimentally and theoretically. Using synchrotron small angle X-ray scattering techniques we find that applying a magnetic field along the main director of the biaxial nematic phase leads to a clear decrease in biaxiality with increasing magnetic field strength. Above a certain magnetic field strength the biaxiality is completely suppressed and the biaxial nematic phase transforms into an ordinary prolate uniaxial nematic phase. In order to interpret the physical mechanism behind this phenomenon, we develop a mean-field theory for the liquid crystal phase behaviour of the suspension. Within this theory the magnetic properties of the particles are modelled by taking into account the effect of both the permanent and the induced magnetic dipoles. The resulting phase diagrams support our experimental findings of the field-induced biaxial nematic to prolate uniaxial nematic transition. They additionally predict that for more plate-like particles, which initially would only display oblate nematic ordering of the shortest axis, the rare biaxial phase can be induced by applying a magnetic field with a carefully chosen field strength, a parameter which can be easily tuned.
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Affiliation(s)
- Anke B G M Leferink op Reinink
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, Padualaan 8, 3584CH Utrecht, The Netherlands.
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28
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Slyusarenko K, Reshetnyak V, Reznikov Y. Magnetic field control of the ordering of two-component suspension of hard rods. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2013; 371:20120250. [PMID: 23459956 DOI: 10.1098/rsta.2012.0250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The Onsager theory of hard rod dispersion in a neutral solvent is extended to a case of two-component dispersion consisting of both non-magnetic and magnetic rods. It was found that the alignment of magneto-sensitive dispersion component by a magnetic field leads to the alignment of non-magnetic component in the dispersion and to an elimination of the isotropic phase. This effect is significant even at low relative concentrations of magnetic rods and leads to a magnetically induced anisotropy in a non-magnetic dispersion of rods mixed with the magnetic ones.
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Affiliation(s)
- K Slyusarenko
- Laboratoire de Physique des Solides CNRS, Université Paris-Sud, Orsay, France
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29
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Wagner J, Märkert C, Fischer B, Müller L. Direction dependent diffusion of aligned magnetic rods by means of x-ray photon correlation spectroscopy. PHYSICAL REVIEW LETTERS 2013; 110:048301. [PMID: 25166207 DOI: 10.1103/physrevlett.110.048301] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Indexed: 06/03/2023]
Abstract
Rodlike hematite particles in suspension align perpendicular to an external magnetic field due to a negative anisotropy of their magnetic susceptibility Δχ. The diffusion tensor consists of two principal constants D(∥) and D(⊥) for the diffusion parallel and perpendicular to the long particle axis. X-ray photon correlation spectroscopy is capable of probing the diffusive motion in optically opaque suspensions of rodlike hematite particles parallel to the direction of the scattering vector Q. Choosing Q parallel or perpendicular to the direction of an external magnetic field H the direction dependent intermediate scattering function is measured by means of x-ray photon correlation spectroscopy. From the intermediate scattering function in both directions the principal diffusion constants D(∥) and D(⊥) are determined. The ratio D(∥)/D(⊥) increases with increasing aspect ratio of the particles and can be described via a rescaled theoretical approach for prolate ellipsoids of revolution.
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Affiliation(s)
- Joachim Wagner
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, 18059 Rostock, Germany
| | - Christian Märkert
- Physikalische Chemie, Universität des Saarlandes, Campus B22, 66123 Saarbrücken, Germany
| | - Birgit Fischer
- Deutsches Elektronensynchrotron, Notkestraße 85, 22607 Hamburg, Germany
| | - Leonard Müller
- Deutsches Elektronensynchrotron, Notkestraße 85, 22607 Hamburg, Germany
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30
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Leferink op Reinink ABGM, van den Pol E, Byelov DV, Petukhov AV, Vroege GJ. Ageing in a system of polydisperse goethite boardlike particles showing rich phase behaviour. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:464127. [PMID: 23114499 DOI: 10.1088/0953-8984/24/46/464127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Using microradian x-ray scattering and polarized light microscopy the rich liquid crystalline phase behaviour of a polydisperse system of chromium-modified goethite particles has been studied for five years. We observe that the particles stay highly mobile over years and the rich phase behaviour keeps developing in novel and even surprising ways. While in many other colloidal systems particle size polydispersity suppresses the formation of ordered phases, goethite particles form multiple coexisting ordered phases. The particle polydispersity problem is then solved by particle exchange between coexisting phases. One usually expects that a less ordered phase (e.g., nematic) is formed first while crystallization of the smectic and columnar crystals might take a longer time. For goethite particles we find the opposite, i.e. the nematic phase grows over years at the expense of a better ordered smectic phase. Moreover, SAXS patterns revealed peak splitting for both the smectic and the columnar phase, meaning that the system displays fractionated crystallization. We further discovered that the centred rectangular columnar phase spontaneously forms out of the simple rectangular columnar phase. The reverse transition is observed as well. We explain the ease of these martensitic transitions by showing how slight rotation and translation of the particles triggers the transition.
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31
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Abécassis B, Lerouge F, Bouquet F, Kachbi S, Monteil M, Davidson P. Aqueous Suspensions of GdPO4 Nanorods: A Paramagnetic Mineral Liquid Crystal. J Phys Chem B 2012; 116:7590-5. [DOI: 10.1021/jp303161a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Benjamin Abécassis
- Laboratoire de Physique des
Solides, Univ. Paris-Sud, CNRS, UMR 8502,
F-91405 Orsay Cedex, France
| | - Frédéric Lerouge
- Laboratoire de Chimie, Université Lyon 1, ENS Lyon, CNRS, UMR 5182,
F-69364 Lyon 07, France
| | - Frédéric Bouquet
- Laboratoire de Physique des
Solides, Univ. Paris-Sud, CNRS, UMR 8502,
F-91405 Orsay Cedex, France
| | - Souad Kachbi
- Laboratory
CSPBAT, Université Paris 13, UMR
7244 CNRS, F-93017
Bobigny, France
| | - Maelle Monteil
- Laboratory
CSPBAT, Université Paris 13, UMR
7244 CNRS, F-93017
Bobigny, France
| | - Patrick Davidson
- Laboratoire de Physique des
Solides, Univ. Paris-Sud, CNRS, UMR 8502,
F-91405 Orsay Cedex, France
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32
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Reufer M, Martinez VA, Schurtenberger P, Poon WCK. Differential dynamic microscopy for anisotropic colloidal dynamics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:4618-24. [PMID: 22324390 DOI: 10.1021/la204904a] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Differential dynamic microscopy (DDM) is a low-cost, high-throughput technique recently developed for characterizing the isotropic diffusion of spherical colloids using white-light optical microscopy. (1) We develop the theory for applying DDM to probe the dynamics of anisotropic colloidal samples such as various ordered phases, or particles interacting with an external field. The q-dependent dynamics can be measured in any direction in the image plane. We demonstrate the method on a dilute aqueous dispersion of anisotropic magnetic particles (hematite) aligned in a magnetic field. The measured diffusion coefficients parallel and perpendicular to the field direction are in good agreement with theoretical values. We show how these measurements allow us to extract the orientational order parameter S(2) of the system.
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Affiliation(s)
- Mathias Reufer
- SUPA and School of Physics Astronomy, The University of Edinburgh, Edinburgh, United Kingdom.
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33
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Kuijk A, Byelov DV, Petukhov AV, van Blaaderen A, Imhof A. Phase behavior of colloidal silica rods. Faraday Discuss 2012. [DOI: 10.1039/c2fd20084h] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Dozov I, Paineau E, Davidson P, Antonova K, Baravian C, Bihannic I, Michot LJ. Electric-Field-Induced Perfect Anti-Nematic Order in Isotropic Aqueous Suspensions of a Natural Beidellite Clay. J Phys Chem B 2011; 115:7751-65. [DOI: 10.1021/jp201201x] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- I. Dozov
- Laboratoire de Physique des Solides, UMR 8502 CNRS−Université Paris-Sud, Bât. 510, 91405 Orsay Cedex, France
| | - E. Paineau
- Laboratoire Environnement et Minéralurgie, Nancy University CNRS-INPL UMR 7569, BP40, 54501 Vandœuvre Cedex, France
| | - P. Davidson
- Laboratoire de Physique des Solides, UMR 8502 CNRS−Université Paris-Sud, Bât. 510, 91405 Orsay Cedex, France
| | - K. Antonova
- Institute of Solid State Physics, Bulgarian Academy of Sciences, Tzarigradsko Chaussee 72, 1784 Sofia, Bulgaria
| | - C. Baravian
- Laboratoire d’Energétique et de Mécanique Théorique et Appliquée, Nancy University UMR 7563 CNRS-INPL-UHP, 2, Avenue de la Forêt de Haye, BP160 54504 Vandœuvre Cedex, France
| | - I. Bihannic
- Laboratoire Environnement et Minéralurgie, Nancy University CNRS-INPL UMR 7569, BP40, 54501 Vandœuvre Cedex, France
| | - L. J. Michot
- Laboratoire Environnement et Minéralurgie, Nancy University CNRS-INPL UMR 7569, BP40, 54501 Vandœuvre Cedex, France
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van den Pol E, Verhoeff AA, Lupascu A, Diaconeasa MA, Davidson P, Dozov I, Kuipers BWM, Thies-Weesie DME, Vroege GJ. Magnetic-field-induced nematic-nematic phase separation and droplet formation in colloidal goethite. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:194108. [PMID: 21525548 DOI: 10.1088/0953-8984/23/19/194108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We demonstrate the suitability of polarization microscopy to study the recently discovered (parallel) nematic-(perpendicular) nematic phase separation. This novel type of phase transition is induced by applying an external magnetic field to a nematic liquid crystal of boardlike colloidal goethite and is due to an interplay between the intrinsic magnetic properties of goethite and the collective effect of liquid crystal formation. It is shown that the intense ochre colour of goethite does not preclude the use of polarization microscopy and interference colours, and that dichroism can give valuable qualitative information on the nature of the phases, their anchoring and their sedimentation and order parameter profiles. We also apply these techniques to study 'nematic-nematic tactoids': nematic droplets sedimenting within a nematic medium with mutually perpendicular orientations.
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Affiliation(s)
- E van den Pol
- Van' t Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
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Verhoeff A, Brand R, Lekkerkerker H. Tuning the birefringence of the nematic phase in suspensions of colloidal gibbsite platelets. Mol Phys 2011. [DOI: 10.1080/00268976.2011.559006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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37
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Märkert C, Fischer B, Wagner J. Small-angle scattering from spindle-shaped colloidal hematite particles in external magnetic fields. J Appl Crystallogr 2011. [DOI: 10.1107/s0021889811009617] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
In the presence of phosphate anions, spindle-shaped mesoscale hematite particles can be preparedviacontrolled precipitation of iron(III) chloride. The aspect ratio of the particles is determined by the concentration of phosphate anions selectively covering specific crystal surfaces and thus enabling anisotropic growth of the particles. The scattering function for suspensions of polydisperse spindles is derived and used to analyse the small-angle scattering resulting from these particles. In the presence of an external magnetic field, the particles align perpendicular to the field direction as a result of the negative anisotropy of their magnetic susceptibility \Delta\chi. Hereby, an isotropic–nematic phase transition can be induced in external magnetic fields.
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Sklute EC, Eguchi M, Henderson CN, Angelone MS, Yennawar HP, Mallouk TE. Orientation of Diamagnetic Layered Transition Metal Oxide Particles in 1-Tesla Magnetic Fields. J Am Chem Soc 2011; 133:1824-31. [DOI: 10.1021/ja107090n] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Elizabeth C. Sklute
- Department of Chemistry, ‡Materials Research Institute, and §Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Miharu Eguchi
- Department of Chemistry, ‡Materials Research Institute, and §Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Camden N. Henderson
- Department of Chemistry, ‡Materials Research Institute, and §Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mark S. Angelone
- Department of Chemistry, ‡Materials Research Institute, and §Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Hemant P. Yennawar
- Department of Chemistry, ‡Materials Research Institute, and §Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Thomas E. Mallouk
- Department of Chemistry, ‡Materials Research Institute, and §Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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van den Pol E, Petukhov AV, Thies-Weesie DM, Byelov DV, Vroege GJ. Liquid crystal phase behavior of sterically-stabilized goethite. J Colloid Interface Sci 2010; 352:354-8. [PMID: 20880536 DOI: 10.1016/j.jcis.2010.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 09/01/2010] [Accepted: 09/02/2010] [Indexed: 11/24/2022]
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40
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van den Pol E, Lupascu A, Davidson P, Vroege GJ. The isotropic-nematic interface of colloidal goethite in an external magnetic field. J Chem Phys 2010; 133:164504. [DOI: 10.1063/1.3498738] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Constantin D, Davidson P, Chanéac C. Lyotropic lamellar phase doped with a nematic phase of magnetic nanorods. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:4586-4589. [PMID: 20180581 DOI: 10.1021/la100045r] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report the elaboration of a hybrid mesophase combining the lamellar order of a lyotropic system of nonionic surfactant and the nematic order of a concentrated solution of inorganic nanorods confined between the surfactant layers. Highly aligned samples of this mesophase can be obtained by thermal annealing, and the orientation of the nanorods is readily controlled with a magnetic field. High-resolution synchrotron X-ray scattering and polarized optical microscopy show that, compared to their isolated counterparts, both the nematic and lamellar orders are altered, demonstrating their interplay.
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Affiliation(s)
- Doru Constantin
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS, UMR8502, 91405 Orsay, France.
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42
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Poulos AS, Constantin D, Davidson P, Pansu B, Freyssingeas É, Madsen A, Chanéac C. Communications: Short-range dynamics of a nematic liquid-crystalline phase. J Chem Phys 2010; 132:091101. [DOI: 10.1063/1.3330920] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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43
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Segal I, Zablotskaya A, Lukevics E, Maiorov M, Zablotsky D, Blums E, Mishnev A, Georgieva R, Shestakova I, Gulbe A. Preparation and cytotoxic properties of goethite-based nanoparticles covered with decyldimethyl(dimethylaminoethoxy) silane methiodide. Appl Organomet Chem 2010. [DOI: 10.1002/aoc.1573] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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44
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Zablotskaya A, Segal I, Lukevics E. Iron oxide-based magnetic nanostructures bearing cytotoxic organosilicon molecules for drug delivery and therapy. Appl Organomet Chem 2010. [DOI: 10.1002/aoc.1605] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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van den Pol E, Petukhov AV, Thies-Weesie DME, Vroege GJ. Simple rectangular columnar phase of goethite nanorods and its martensitic transition to the centered rectangular columnar phase. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:1579-1582. [PMID: 20050610 DOI: 10.1021/la9042217] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Using high-resolution small-angle X-ray scattering, we observed a new type of the columnar phase with a simple rectangular (R(S)) structure in colloidal goethite dispersions. Furthermore, it displays a martensitic transition into the usual centered rectangular (R(C)) structure in an external magnetic field. The findings are rationalized in terms of entropic effects within a simple cell model. We interpret the results as an effect of the particle shape and the available degrees of freedom on the delicate balance between the space available for particle translations and rotations within the two structures.
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Affiliation(s)
- Esther van den Pol
- Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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Avendaño C, Müller EA. Liquid crystalline and antinematic behavior of shape-persistent macrocycles from molecular-dynamics simulations. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:061702. [PMID: 20365180 DOI: 10.1103/physreve.80.061702] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Indexed: 05/29/2023]
Abstract
In this work we present a molecular-dynamics study of a coarse-grained (CG) model for a system of planar shape-persistent macrocycles (SPMs). SPMs are synthetic organic rigid macromolecules typically comprised of meta- and para-aromatics groups connected by acetylene and/or diacetylene units. In the CG model, each SPM is represented as a rigid hexagonal arrangement of 24 soft-repulsive spheres, resembling a large ring or hoop. The supramolecular arrangement of these macrocycles at high pressures is studied using N-P-T molecular-dynamics simulation both by expansion of an initial hexagonal lattice structure and also by compression of an isotropic phase. In both cases, systems under consideration exhibit an isotropic-smectic-A phase transition, which is detected by monitoring relevant order parameters and analyzing snapshots of equilibrium configurations. The smectic-A phase is unique; although the molecules form layers, the system presents antinematic order where the orientation of the molecular axes is perpendicular to the direction of the layers themselves. Due to their planar geometry, the SPM molecules would be expected to form columnar or nematic phases. On the contrary, these phases seem suppressed by a novel smectic-A phase, formed by the mutual interpenetration of the cycles. These results are a unique example of how molecular nonconvexity can, by itself, induce mesomorphism in anisotropic systems.
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Affiliation(s)
- Carlos Avendaño
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
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Synthesis of Goethite by Separation of the Nucleation and Growth Processes of Ferrihydrite Nanoparticles Using Microfluidics. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200805933] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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48
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Pacifico J, van Leeuwen YM, Spuch-Calvar M, Sánchez-Iglesias A, Rodríguez-Lorenzo L, Pérez-Juste J, Pastoriza-Santos I, Liz-Marzán LM. Field gradient imaging of nanoparticle systems: analysis of geometry and surface coating effects. NANOTECHNOLOGY 2009; 20:095708. [PMID: 19417504 DOI: 10.1088/0957-4484/20/9/095708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In this work we compare the standard imaging of various types of nanoparticles deposited on surfaces by atomic force microscopy (AFM) with a complementary analysis of the same samples by either electrostatic force microscopy (EFM) or magnetic force microscopy (MFM). Experiments were carried out on gold nanoparticles (decahedrons and stars) and two different iron oxide systems: goethite (alpha-FeOOH) and hematite (alpha-Fe(2)O(3)). Regardless of the particular geometry, the EFM signal appears to be stronger on edges or tips of pure gold nanoparticles. Both EFM and MFM experiments were also carried out on iron oxide particles. Apart from the structural analysis, we analyzed the influence of a shell layer deposited on the gold and iron oxide particles, the shell being amorphous SiO(2). Although the silica layer was found to have an insulating effect around the particles, in all cases EFM/MFM measurements could still be performed by the proper choice of the scan lift height (with an eventual slight increase of the sample bias, where applicable).
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Affiliation(s)
- J Pacifico
- Departamento de Química Física, and Unidad Asociada CSIC, Universidade de Vigo, Vigo, Spain.
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49
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Abou-Hassan A, Sandre O, Neveu S, Cabuil V. Synthesis of Goethite by Separation of the Nucleation and Growth Processes of Ferrihydrite Nanoparticles Using Microfluidics. Angew Chem Int Ed Engl 2009; 48:2342-5. [DOI: 10.1002/anie.200805933] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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50
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van den Pol E, Thies-Weesie DME, Petukhov AV, Vroege GJ, Kvashnina K. Influence of polydispersity on the phase behavior of colloidal goethite. J Chem Phys 2008; 129:164715. [PMID: 19045306 DOI: 10.1063/1.2999405] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The effect of fractionation on the phase behavior of colloidal goethite dispersions with different polydispersities (17%, 35%, and 55% in length) has been studied by small angle x-ray scattering and transmission electron microscopy. All systems show at least nematic and smectic phases. The occurrence of the latter phase at such a high polydispersity is remarkable. It is shown that in the highly polydisperse systems strong fractionation occurs, which is able to reduce the local length polydispersity up to a factor of 2. A columnar phase was only found in the 35% and 55% polydisperse systems. It seems that the columnar phase accommodates the particles that do not fit into the smectic layers and, thus, reduces the length polydispersity within the smectic phase even further. The fact that a columnar phase was not found in the system of lowest polydispersity indicates that the smectic phase is the most stable phase at higher concentrations.
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Affiliation(s)
- E van den Pol
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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