1
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Xu M, Lei L, Hu H, Chen Y, Yang X, Yu K, Cao B, Zhang X, Jiang X, Yao C, Yang H. Construction of Ferric-Oxide-Doped Nickel-Iron Hydroxide Electrocatalysts by Magnetic-Field-Assisted Chemical Corrosion toward Boosted Oxygen Evolution Reaction. Molecules 2024; 29:3127. [PMID: 38999079 PMCID: PMC11242944 DOI: 10.3390/molecules29133127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Revised: 06/22/2024] [Accepted: 06/27/2024] [Indexed: 07/14/2024] Open
Abstract
Transition-metal-based oxygen evolution reaction (OER) catalysts have attracted widespread attention due to their inexpensive prices, unique layered structures, and rich active sites. Currently, designing low-cost, sustainable, and simple synthesis methods is essential for the application of transition-metal-based catalysts. Here, magnetic field (MF)-assisted chemical corrosion, as a novel technology, is adopted to construct superior OER electrocatalysts. The produced Ni(Fe)(OH)2-Fe2O3 electrode exhibits an overpotential of 272 mV at a current density of 100 mA cm-2, presenting a 64 mV reduction compared to the electrode without an MF. The experimental results indicate that an MF can induce the directional growth of Fe2O3 rods and reduce their accumulation. In addition, an external MF is beneficial for the lattice dislocation of the obtained catalysts, which can increase the surface free energy, thus reducing the activation energy and accelerating the electrochemical reaction kinetics. This work effectively combines a magnetic field with chemical corrosion and electrochemical energy, which offers a novel strategy for the large-scale development of environmentally friendly and superior electrocatalysts.
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Affiliation(s)
- Mengdie Xu
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Wuhan Institute of Technology, No. 206 Guanggu 1st Road, Wuhan 430205, China
| | - Ling Lei
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Wuhan Institute of Technology, No. 206 Guanggu 1st Road, Wuhan 430205, China
| | - Huilin Hu
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Wuhan Institute of Technology, No. 206 Guanggu 1st Road, Wuhan 430205, China
| | - Yana Chen
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Wuhan Institute of Technology, No. 206 Guanggu 1st Road, Wuhan 430205, China
| | - Xuchao Yang
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Wuhan Institute of Technology, No. 206 Guanggu 1st Road, Wuhan 430205, China
| | - Kaige Yu
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Wuhan Institute of Technology, No. 206 Guanggu 1st Road, Wuhan 430205, China
| | - Bingying Cao
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Wuhan Institute of Technology, No. 206 Guanggu 1st Road, Wuhan 430205, China
| | - Xianzheng Zhang
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Wuhan Institute of Technology, No. 206 Guanggu 1st Road, Wuhan 430205, China
| | - Xueliang Jiang
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Wuhan Institute of Technology, No. 206 Guanggu 1st Road, Wuhan 430205, China
| | - Chu Yao
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Wuhan Institute of Technology, No. 206 Guanggu 1st Road, Wuhan 430205, China
| | - Huan Yang
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Wuhan Institute of Technology, No. 206 Guanggu 1st Road, Wuhan 430205, China
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2
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Marni S, Caimi F, Barboza R, Clark N, Bellini T, Lucchetti L. Fluid jets and polar domains, on the relationship between electromechanical instability and topology in ferroelectric nematic liquid crystal droplets. SOFT MATTER 2024; 20:4878-4885. [PMID: 38819946 DOI: 10.1039/d4sm00317a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Abstract
Ferroelectric nematic liquid crystals are a class of recently discovered fluid materials formed by highly polar molecules that spontaneously align along a common direction, giving rise to a macroscopic polarization P. Since the polarization vector is locally collinear to the optical axis n, the study of the spatial patterns of n enables deducing the structure of P. We have carried on such topological study on ferroelectric nematic droplets confined between two solid ferroelectric substrates both when the droplet is in equilibrium and during a jet-emission phase that takes place when the solid surfaces become sufficiently charged. We find that in equilibrium the droplet splits in striped domains in which P has alternating directions. When these domains extend close to the droplets' perimeter, P adopts a π-twisted structure to minimize accumulation of polarization charges. As the substrate surface charge is increased above threshold, fluid jets are emitted with a quasi-periodic pattern, a behaviour suggesting that their location is governed by an electrofluidic instability on the droplets' rim, in turn indicating the absence of specific trigger points. Soon after their emission, the jet periodicity is lost; some jets retract while other markedly grow. In this second regime, jets that grow are those that more easily connect to polar domains with P along the jet axis. Occasionally, ejection of isolated spikes also occurs, revealing locations where polarization charges have accumulated because of topological patterns extending on length scales smaller than the typical domain size.
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Affiliation(s)
- Stefano Marni
- Dipartimento SIMAU, Università Politecnica delle Marche, via Brecce Bianche, Ancona 60131, Italy.
| | - Federico Caimi
- Medical Biotechnology and Translational Medicine Dept., University of Milano, Segrate 20054, Italy.
| | - Raouf Barboza
- Dipartimento SIMAU, Università Politecnica delle Marche, via Brecce Bianche, Ancona 60131, Italy.
| | - Noel Clark
- Department of Physics, Soft Materials Research Center, University of Colorado, Boulder, CO, 80305, USA
| | - Tommaso Bellini
- Medical Biotechnology and Translational Medicine Dept., University of Milano, Segrate 20054, Italy.
| | - Liana Lucchetti
- Dipartimento SIMAU, Università Politecnica delle Marche, via Brecce Bianche, Ancona 60131, Italy.
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3
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Rosenberg M, Kantorovich SS, Ivanov AO, Camp PJ. Structure and dynamics in suspensions of magnetic platelets. NANOSCALE 2024; 16:10250-10261. [PMID: 38713488 DOI: 10.1039/d4nr01120a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
In this research, we employ Brownian dynamics simulations, density functional theory, and mean-field theory to explore the profound influence of shape anisotropy of magnetic nanoplatelets on suspension magnetic response. Each platelet is modelled as an oblate cylinder with a longitudinal point dipole, with an emphasis on strong dipolar interactions conducive to self-assembly. We investigate static structural and magnetic properties, characterising the system through pair distribution function, static structure factor, and cluster-size distribution. The findings demonstrate that shape-specific interactions and clustering lead to significant changes in reorientational relaxation times. Under zero field, distinctive modes in the dynamic magnetic susceptibility identify individual particles and particle clusters. In the presence of an applied field, the characteristic relaxation time of clusters increases, while that of single particles decreases. This research provides insights into the intricate interplay between shape anisotropy, clustering, and magnetic response in platelet suspensions, offering valuable perspectives for recent experimental observations.
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Affiliation(s)
- Margaret Rosenberg
- Faculty of Physics, University of Vienna, Kolingasse 14-16, Vienna 1090, Austria.
- Research Platform MMM, University of Vienna, Oskar-Morgenstern-Platz 1, Vienna, Austria
| | - Sofia S Kantorovich
- Faculty of Physics, University of Vienna, Kolingasse 14-16, Vienna 1090, Austria.
- Research Platform MMM, University of Vienna, Oskar-Morgenstern-Platz 1, Vienna, Austria
| | - Alexey O Ivanov
- Ural Federal University, Lenin Avenue 51, Ekaterinburg, 620000, Russia
| | - Philip J Camp
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, UK
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4
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Damoc M, Tiron V, Tugui C, Varganici CD, Stoica AC, Novitchi G, Dascalu M, Cazacu M. Ferronematic Co(II) Complex: An Active Filler for Magnetically Actuated Soft Materials. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2307006. [PMID: 37992252 DOI: 10.1002/smll.202307006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 11/08/2023] [Indexed: 11/24/2023]
Abstract
Ferronematics that are generally based on nematic liquid crystals (LCs) doped with magnetic nanoparticles, synergistically taking advantage of the anisotropic and flow characteristics of the nematic host and the magnetic susceptibility of the dopant, have powerful applications as magnetically actuated soft materials. In this work, a Co(II) complex, which alone presents both characteristics, is built with a salen-type ligand 3,5-dichlorosubstituted at the aromatic nuclei and has a tetramethyldisiloxane spacer, which makes it one of the few metallomesogens containing this structural motif. Paramagnetic crystals, through heat treatment above 110 °C, change into magnetic nematic LCs. Applying a perpendicular magnetic field of 50 mT, the nematic droplets align two by two through dipole-dipole interactions. By incorporating it into a silicone matrix consisting mainly of polydimethylsiloxane, a 3D printable ink is formulated and crosslinked under various shapes. In this environment, the cobalt complex is stabilized in an LC state at room temperature and, due to its anisotropy, facilitates the mechanical response to magnetic stimuli. The resulting objects can be easily manipulated on fluid or rough surfaces using external magnetic fields, behave like magnets by themselves, and show reversible locomotion.
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Affiliation(s)
- Madalin Damoc
- Department of Inorganic Polymers, "Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi, 700487, Romania
| | - Vasile Tiron
- Research Center on Advanced Materials and Technologies, Department of Exact and Natural Sciences, Institute of Interdisciplinary Research, Alexandru Ioan Cuza University of Iasi, Blvd. Carol no. 11, Iasi, 700506, Romania
| | - Codrin Tugui
- Department of Inorganic Polymers, "Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi, 700487, Romania
| | - Cristian-Dragos Varganici
- Centre of Advanced Research in Bionanoconjugates and Biopolymers, "Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi, 700487, Romania
| | - Alexandru-Constantin Stoica
- Department of Inorganic Polymers, "Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi, 700487, Romania
| | - Ghenadie Novitchi
- Laboratoire National des Champs Magnétiques Intenses, CNRS UPR 3228, 25 Rue des Martyrs, Grenoble, 38042, France
| | - Mihaela Dascalu
- Department of Inorganic Polymers, "Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi, 700487, Romania
| | - Maria Cazacu
- Department of Inorganic Polymers, "Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi, 700487, Romania
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5
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Vilfan M, Lampret B, Gregorin Ž, Cmok L, Vilfan A, Klepp J, Kohlbrecher J, Hribar Boštjančič P, Lisjak D, Mertelj A. Spontaneous Chiral Symmetry Breaking and Lane Formation in Ferromagnetic Ferrofluids. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2304387. [PMID: 37643398 DOI: 10.1002/smll.202304387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/04/2023] [Indexed: 08/31/2023]
Abstract
Ferromagnetic ferrofluids are synthetic materials consisting of magnetic nanoplatelets dispersed in an isotropic fluid. Their main characteristics are the formation of stable magnetic domains and the presence of macroscopic magnetization even in the absence of a magnetic field. Here, the authors report on the experimental observation of spontaneous stripe formation in a ferromagnetic ferrofluid in the presence of an oscillating external magnetic field. The striped structure is identified as elongated magnetic domains, which exhibit reorientation upon reversal of the magnetic field. The stripes are oriented perpendicular to the magnetic field and are separated by alternating flow lanes. The velocity profile is measured using a space-time correlation technique that follows the motion of the thermally excited fluctuations in the sample. The highest velocities are found in the depleted regions between individual domains and reach values up to several µm s-1 . The fluid in adjacent lanes moves in the opposite directions despite the applied magnetic field being uniform. The formation of bidirectional flow lanes can be explained by alternating rotation of magnetic nanoparticles in neighboring stripes, which indicates spontaneous breaking of the chiral symmetry in the sample.
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Affiliation(s)
- Mojca Vilfan
- J. Stefan Institute, Ljubljana, 1000, Slovenia
- Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, 1000, Slovenia
| | | | | | - Luka Cmok
- J. Stefan Institute, Ljubljana, 1000, Slovenia
| | - Andrej Vilfan
- J. Stefan Institute, Ljubljana, 1000, Slovenia
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077, Göttingen, Germany
| | - Jürgen Klepp
- Faculty of Physics, University of Vienna, Vienna, 1090, Austria
| | - Joachim Kohlbrecher
- Laboratory for Neutron Scattering and Imaging, PSI, Villigen, 5303, Switzerland
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6
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Fan Q, Li Z, Wu C, Yin Y. Magnetically Induced Anisotropic Interaction in Colloidal Assembly. PRECISION CHEMISTRY 2023; 1:272-298. [PMID: 37529717 PMCID: PMC10389807 DOI: 10.1021/prechem.3c00012] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 05/28/2023] [Accepted: 05/30/2023] [Indexed: 08/03/2023]
Abstract
The wide accessibility to nanostructures with high uniformity and controllable sizes and morphologies provides great opportunities for creating complex superstructures with unique functionalities. Employing anisotropic nanostructures as the building blocks significantly enriches the superstructural phases, while their orientational control for obtaining long-range orders has remained a significant challenge. One solution is to introduce magnetic components into the anisotropic nanostructures to enable precise control of their orientations and positions in the superstructures by manipulating magnetic interactions. Recognizing the importance of magnetic anisotropy in colloidal assembly, we provide here an overview of magnetic field-guided self-assembly of magnetic nanoparticles with typical anisotropic shapes, including rods, cubes, plates, and peanuts. The Review starts with discussing the magnetic energy of nanoparticles, appreciating the vital roles of magneto-crystalline and shape anisotropies in determining the easy magnetization direction of the anisotropic nanostructures. It then introduces superstructures assembled from various magnetic building blocks and summarizes their unique properties and intriguing applications. It concludes with a discussion of remaining challenges and an outlook of future research opportunities that the magnetic assembly strategy may offer for colloidal assembly.
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Affiliation(s)
- Qingsong Fan
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Zhiwei Li
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Chaolumen Wu
- 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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7
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Lisjak D, Arčon I, Poberžnik M, Herrero-Saboya G, Tufani A, Mavrič A, Valant M, Boštjančič PH, Mertelj A, Makovec D, Martin-Samos L. Saturation magnetisation as an indicator of the disintegration of barium hexaferrite nanoplatelets during the surface functionalisation. Sci Rep 2023; 13:1092. [PMID: 36658162 PMCID: PMC9852462 DOI: 10.1038/s41598-023-28431-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 01/18/2023] [Indexed: 01/20/2023] Open
Abstract
Barium hexaferrite nanoplatelets (BHF NPLs) are permanent nanomagnets with the magnetic easy axis aligned perpendicular to their basal plane. By combining this specific property with optimised surface chemistry, novel functional materials were developed, e.g., ferromagnetic ferrofluids and porous nanomagnets. We compared the interaction of chemically different phosphonic acids, hydrophobic and hydrophilic with 1-4 phosphonic groups, with BHF NPLs. A decrease in the saturation magnetisation after functionalising the BHF NPLs was correlated with the mass fraction of the nonmagnetic coating, whereas the saturation magnetisation of the NPLs coated with a tetraphosphonic acid at 80 °C was significantly lower than expected. We showed that such a substantial decrease in the saturation magnetisation originates from the disintegration of BHF NPLs, which was observed with atomic-resolution scanning transmission electron microscopy and confirmed by a computational study based on state-of-the-art first-principles calculations. Fe K-edge XANES (X-ray absorption near-edge structure) and EXAFS (Extended X-ray absorption fine structure) combined with Fourier-transformed infrared (FTIR) spectroscopy confirmed the formation of an Fe-phosphonate complex on the partly decomposed NPLs. Comparing our results with other functionalised magnetic nanoparticles confirmed that saturation magnetisation can be exploited to identify the disintegration of magnetic nanoparticles when insoluble disintegration products are formed.
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Affiliation(s)
- Darja Lisjak
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, 1000 Ljubljana, Slovenia
| | - Iztok Arčon
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, 1000 Ljubljana, Slovenia ,grid.438882.d0000 0001 0212 6916University of Nova Gorica, 5000 Nova Gorica, Slovenia
| | - Matic Poberžnik
- grid.472635.10000 0004 6476 9521CNR-IOM, Democritos National Simulation Center, Istituto Officina dei Materiali, c/o SiSSA, 34136 Trieste, Italy
| | - Gabriela Herrero-Saboya
- grid.472635.10000 0004 6476 9521CNR-IOM, Democritos National Simulation Center, Istituto Officina dei Materiali, c/o SiSSA, 34136 Trieste, Italy
| | - Ali Tufani
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, 1000 Ljubljana, Slovenia
| | - Andraž Mavrič
- grid.438882.d0000 0001 0212 6916University of Nova Gorica, 5000 Nova Gorica, Slovenia
| | - Matjaz Valant
- grid.438882.d0000 0001 0212 6916University of Nova Gorica, 5000 Nova Gorica, Slovenia
| | - Patricija Hribar Boštjančič
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, 1000 Ljubljana, Slovenia ,grid.445211.7Jožef Stefan International Postgraduate School, 1000 Ljubljana, Slovenia
| | - Alenka Mertelj
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, 1000 Ljubljana, Slovenia
| | - Darko Makovec
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, 1000 Ljubljana, Slovenia
| | - Layla Martin-Samos
- grid.472635.10000 0004 6476 9521CNR-IOM, Democritos National Simulation Center, Istituto Officina dei Materiali, c/o SiSSA, 34136 Trieste, Italy
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8
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Qiao S, Li S, Song Q, Liu B. Shape-Tunable Biconcave Disc-Like Polymer Particles by Swelling-Induced Phase Separation of Seeded Particles with Hydrophilic Shells. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:1190-1197. [PMID: 36621841 DOI: 10.1021/acs.langmuir.2c02995] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Anisotropic shape-tunable polymer particles have gained significant attention for their wide applications, and their performances are usually strongly correlated to their shapes. In contrast to convex particles, the synthesis of highly uniform concave polymer particles remains a great challenge. Here, we present a facile and effective route to synthesize biconcave polystyrene (PS) discs by swelling-induced phase separation of hydrophilically modified PS microspheres and report an unexpected finding that even a tiny amount of hydrophilic units that were incorporated into PS microspheres can significantly change the shape of phase interfaces, resulting in the transformation of disc shapes from convex to flat to concave. This is realized by several typical hydrophilic monomers, such as sodium styrene sulfonate (NaSS), acrylic acid (AA), or (2-(methacryloyloxy)ethyl)trimethylammonium chloride (METAC). The effect of the distribution of hydrophilic units in microspheres was investigated, and the mechanism of shape tuning has been discussed. The curvatures of the bottom surfaces of discs show a strong correlation to the content of hydrophilic units. In particular, we emphasize that the shape control method is general since it does not depend on specific hydrophilic units. This research paves the way for precisely structuring polymer particle shapes, which is important for polymer particles to be used for self-assembly, diffusion, rheology, transport, filler, and many other applications.
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Affiliation(s)
- Shuoyuan Qiao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing100190, China
- University of Chinese Academy of Sciences, Beijing100149, China
| | - Shanshan Li
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing100190, China
- University of Chinese Academy of Sciences, Beijing100149, China
| | - Qing Song
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing100190, China
- University of Chinese Academy of Sciences, Beijing100149, China
| | - Bing Liu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing100190, China
- University of Chinese Academy of Sciences, Beijing100149, China
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9
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Gregorin Ž, Sebastián N, Osterman N, Hribar Boštjančič P, Lisjak D, Mertelj A. Dynamics of domain formation in a ferromagnetic fluid. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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10
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Budinski V, Pevec S, Čampelj S, Mertelj A, Lisjak D, Donlagic D. Miniature magneto-optic angular position sensor. OPTICS LETTERS 2022; 47:4696-4699. [PMID: 36107066 DOI: 10.1364/ol.470646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/23/2022] [Indexed: 06/15/2023]
Abstract
This Letter describes a miniature Fabry-Perot, contactless, magneto-optic sensor for angular position measurement. The sensor utilizes a magneto-optic fluid comprising barium hexaferrite nanoplatelets that become birefringent in the presence of an external magnetic field and a compact fiber-optic sensor system for tracking the liquid's optical axis direction. An efficient temperature compensation system is provided which allows the use of otherwise highly temperature-sensitive magneto-optic liquids. An unambiguous measurement range of 90° and a resolution of better than 0.05° are demonstrated experimentally.
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11
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Küster M, Ludwig F, Eremin A, Boštjančič PH, Lisjak D, Sebastián N, Mertelj A, Nádasi H. Magnetic dynamics in suspensions of ferrimagnetic platelets. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119484] [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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12
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New Insights into Amino-Functionalization of Magnetic Nanoplatelets with Silanes and Phosphonates. NANOMATERIALS 2022; 12:nano12122123. [PMID: 35745462 PMCID: PMC9229317 DOI: 10.3390/nano12122123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/17/2022] [Accepted: 06/17/2022] [Indexed: 02/01/2023]
Abstract
Magnetic nanoplatelets (NPLs) based on barium hexaferrite (BaFe12O19) are suitable for many applications because of their uniaxial magneto-crystalline anisotropy. Novel materials, such as ferroic liquids, magneto-optic composites, and contrast agents for medical diagnostics, were developed by specific surface functionalization of the barium hexaferrite NPLs. Our aim was to amino-functionalize the NPLs’ surfaces towards new materials and applications. The amino-functionalization of oxide surfaces is challenging and has not yet been reported for barium hexaferrite NPLs. We selected two amine ligands with two different anchoring groups: an amino-silane and an amino-phosphonate. We studied the effect of the anchoring group, backbone structure, and processing conditions on the formation of the respective surface coatings. The core and coated NPLs were examined with transmission electron microscopy, and their room-temperature magnetic properties were measured. The formation of coatings was followed by electrokinetic measurements, infrared and mass spectroscopies, and thermogravimetric analysis. The most efficient amino-functionalization was enabled by (i) amino-silanization of the NPLs precoated with amorphous silica with (3-aminopropyl)triethoxysilane and (ii) slow addition of amino-phosphonate (i.e., sodium alendronate) to the acidified NPL suspension at 80 °C.
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13
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Kim D, Ndaya D, Bosire R, Masese FK, Li W, Thompson SM, Kagan CR, Murray CB, Kasi RM, Osuji CO. Dynamic magnetic field alignment and polarized emission of semiconductor nanoplatelets in a liquid crystal polymer. Nat Commun 2022; 13:2507. [PMID: 35523816 PMCID: PMC9076605 DOI: 10.1038/s41467-022-30200-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 04/20/2022] [Indexed: 11/29/2022] Open
Abstract
Reconfigurable arrays of 2D nanomaterials are essential for the realization of switchable and intelligent material systems. Using liquid crystals (LCs) as a medium represents a promising approach, in principle, to enable such control. In practice, however, this approach is hampered by the difficulty of achieving stable dispersions of nanomaterials. Here, we report on good dispersions of pristine CdSe nanoplatelets (NPLs) in LCs, and reversible, rapid control of their alignment and associated anisotropic photoluminescence, using a magnetic field. We reveal that dispersion stability is greatly enhanced using polymeric, rather than small molecule, LCs and is considerably greater in the smectic phases of the resulting systems relative to the nematic phases. Aligned composites exhibit highly polarized emission that is readily manipulated by field-realignment. Such dynamic alignment of optically-active 2D nanomaterials may enable the development of programmable materials for photonic applications and the methodology can guide designs for anisotropic nanomaterial composites for a broad set of related nanomaterials. Liquid crystals (LC) are promising materials for the fabrication of reconfigurable arrays of 2D nanomaterials but it remains difficult to achieve stable dispersions of nanomaterials. Here, the authors report on good dispersions of pristine CdSe nanoplatelets (NPLs) in LCs, and reversible, rapid control of their alignment and associated anisotropic photoluminescence using a magnetic field.
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Affiliation(s)
- Dahin Kim
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Dennis Ndaya
- Department of Chemistry, University of Connecticut, Storrs, CT, 06269, USA.,Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT, 06269, USA
| | - Reuben Bosire
- Department of Chemistry, University of Connecticut, Storrs, CT, 06269, USA
| | - Francis K Masese
- Department of Chemistry, University of Connecticut, Storrs, CT, 06269, USA
| | - Weixingyue Li
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Sarah M Thompson
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Cherie R Kagan
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA.,Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA.,Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Christopher B Murray
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA.,Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Rajeswari M Kasi
- Department of Chemistry, University of Connecticut, Storrs, CT, 06269, USA.,Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT, 06269, USA
| | - Chinedum O Osuji
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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14
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Socoliuc V, Avdeev MV, Kuncser V, Turcu R, Tombácz E, Vékás L. Ferrofluids and bio-ferrofluids: looking back and stepping forward. NANOSCALE 2022; 14:4786-4886. [PMID: 35297919 DOI: 10.1039/d1nr05841j] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Ferrofluids investigated along for about five decades are ultrastable colloidal suspensions of magnetic nanoparticles, which manifest simultaneously fluid and magnetic properties. Their magnetically controllable and tunable feature proved to be from the beginning an extremely fertile ground for a wide range of engineering applications. More recently, biocompatible ferrofluids attracted huge interest and produced a considerable increase of the applicative potential in nanomedicine, biotechnology and environmental protection. This paper offers a brief overview of the most relevant early results and a comprehensive description of recent achievements in ferrofluid synthesis, advanced characterization, as well as the governing equations of ferrohydrodynamics, the most important interfacial phenomena and the flow properties. Finally, it provides an overview of recent advances in tunable and adaptive multifunctional materials derived from ferrofluids and a detailed presentation of the recent progress of applications in the field of sensors and actuators, ferrofluid-driven assembly and manipulation, droplet technology, including droplet generation and control, mechanical actuation, liquid computing and robotics.
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Affiliation(s)
- V Socoliuc
- Romanian Academy - Timisoara Branch, Center for Fundamental and Advanced Technical Research, Laboratory of Magnetic Fluids, Mihai Viteazu Ave. 24, 300223 Timisoara, Romania.
| | - M V Avdeev
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie Str. 6, 141980 Dubna, Moscow Reg., Russia.
| | - V Kuncser
- National Institute of Materials Physics, Bucharest-Magurele, 077125, Romania
| | - Rodica Turcu
- National Institute for Research and Development of Isotopic and Molecular Technologies (INCDTIM), Donat Str. 67-103, 400293 Cluj-Napoca, Romania
| | - Etelka Tombácz
- University of Szeged, Faculty of Engineering, Department of Food Engineering, Moszkvai krt. 5-7, H-6725 Szeged, Hungary.
- University of Pannonia - Soós Ernő Water Technology Research and Development Center, H-8800 Zrínyi M. str. 18, Nagykanizsa, Hungary
| | - L Vékás
- Romanian Academy - Timisoara Branch, Center for Fundamental and Advanced Technical Research, Laboratory of Magnetic Fluids, Mihai Viteazu Ave. 24, 300223 Timisoara, Romania.
- Politehnica University of Timisoara, Research Center for Complex Fluids Systems Engineering, Mihai Viteazul Ave. 1, 300222 Timisoara, Romania
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15
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Hribar Boštjančič P, Gregorin Ž, Sebastián N, Osterman N, Lisjak D, Mertelj A. Isotropic to nematic transition in alcohol ferrofluids of barium hexaferrite nanoplatelets. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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16
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Shuai H, Xiaoni Z, Yan L, Yanle L, Yan D, Lu M, Yingliang S, Wei M. Fabrication method for a magnetically induced highly oriented nanohydroxyapatite/collagen composite. J Appl Biomater Funct Mater 2022; 20:22808000221105727. [PMID: 35787019 DOI: 10.1177/22808000221105727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Both collagen fibres and nanohydroxyapatite crystals have anisotropic magnetisation, which allows them to be oriented by a high magnetic field. Highly oriented nanohydroxyapatite/collagen composites were prepared using a high magnetic field combined with in situ synthesis. These highly oriented composites were investigated and compared with conventional composites. The results showed that the collagen fibres in the magnetically induced highly oriented nanohydroxyapatite/collagen composites had a preferred orientation and smaller molecular spacing, while the nanohydroxyapatite crystals were tightly adhered along the collagen fibre surface. The magnetically induced composites exhibited superior resistance to swelling and degradation along with high compressive strength. This artificial composite, with a structure and composition similar to natural bone, represents a new idea for improving materials for vertical or horizontal bone augmentation.
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Affiliation(s)
- Huang Shuai
- State Key Laboratory of Military Stomatology & National, Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Implant Dentistry & School of Stomatology, The Fourth Military Medical University, Xi' an, China
| | - Zhou Xiaoni
- State Key Laboratory of Military Stomatology & National, Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Implant Dentistry & School of Stomatology, The Fourth Military Medical University, Xi' an, China
| | - Liu Yan
- State Key Laboratory of Military Stomatology & National, Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Implant Dentistry & School of Stomatology, The Fourth Military Medical University, Xi' an, China
| | - Liu Yanle
- State Key Laboratory of Military Stomatology & National, Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Implant Dentistry & School of Stomatology, The Fourth Military Medical University, Xi' an, China
| | - Duan Yan
- State Key Laboratory of Military Stomatology & National, Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Implant Dentistry & School of Stomatology, The Fourth Military Medical University, Xi' an, China
| | - Meng Lu
- Sannie Bioengineering Technology Co., Ltd., Tianjin, China
| | - Song Yingliang
- State Key Laboratory of Military Stomatology & National, Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Implant Dentistry & School of Stomatology, The Fourth Military Medical University, Xi' an, China
| | - Ma Wei
- State Key Laboratory of Military Stomatology & National, Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Implant Dentistry & School of Stomatology, The Fourth Military Medical University, Xi' an, China
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17
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Kumar TSJ, Arumugam M. Optical Properties of Magnetic Nanoalloys and Nanocomposites. HANDBOOK OF MAGNETIC HYBRID NANOALLOYS AND THEIR NANOCOMPOSITES 2022:547-573. [DOI: 10.1007/978-3-030-90948-2_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
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18
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Kumar TSJ, Arumugam M. Optical Properties of Magnetic Nanoalloys and Nanocomposites. HANDBOOK OF MAGNETIC HYBRID NANOALLOYS AND THEIR NANOCOMPOSITES 2022:1-27. [DOI: 10.1007/978-3-030-34007-0_18-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 02/25/2022] [Indexed: 06/16/2023]
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19
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Spontaneous helielectric nematic liquid crystals: Electric analog to helimagnets. Proc Natl Acad Sci U S A 2021; 118:2111101118. [PMID: 34642251 DOI: 10.1073/pnas.2111101118] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2021] [Indexed: 11/18/2022] Open
Abstract
Recently, a type of ferroelectric nematic fluid has been discovered in liquid crystals in which the molecular polar nature at molecule level is amplified to macroscopic scales through a ferroelectric packing of rod-shaped molecules. Here, we report on the experimental proof of a polar chiral liquid matter state, dubbed helielectric nematic, stabilized by the local polar ordering coupled to the chiral helicity. This helielectric structure carries the polar vector rotating helically, analogous to the magnetic counterpart of helimagnet. The helielectric state can be retained down to room temperature and demonstrates gigantic dielectric and nonlinear optical responses. This matter state opens a new chapter for developing the diverse polar liquid crystal devices.
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20
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Mandle RJ, Sebastián N, Martinez-Perdiguero J, Mertelj A. On the molecular origins of the ferroelectric splay nematic phase. Nat Commun 2021; 12:4962. [PMID: 34400645 PMCID: PMC8367997 DOI: 10.1038/s41467-021-25231-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 07/13/2021] [Indexed: 11/25/2022] Open
Abstract
Nematic liquid crystals have been known for more than a century, but it was not until the 60s–70s that, with the development of room temperature nematics, they became widely used in applications. Polar nematic phases have been long-time predicted, but have only been experimentally realized recently. Synthesis of materials with nematic polar ordering at room temperature is certainly challenging and requires a deep understanding of its formation mechanisms, presently lacking. Here, we compare two materials of similar chemical structure and demonstrate that just a subtle change in the molecular structure enables denser packing of the molecules when they exhibit polar order, which shows that reduction of excluded volume is in the origin of the polar nematic phase. Additionally, we propose that molecular dynamics simulations are potent tools for molecular design in order to predict, identify and design materials showing the polar nematic phase and its precursor nematic phases. Nematic liquid crystals with polar order bear great potential for many applications but their rational design is difficult. Mandle et al. outline a set of design principles for this new phase of matter, guided by experiments and simulation, showing polar order to be driven by steric interactions.
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Affiliation(s)
- Richard J Mandle
- School of Physics and Astronomy, University of Leeds, Leeds, UK. .,Department of Chemistry, University of York, York, UK.
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21
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Lu J, Bu X, Zhang X, Liu B. Self-assembly of shape-tunable oblate colloidal particles into orientationally ordered crystals, glassy crystals and plastic crystals. SOFT MATTER 2021; 17:6486-6494. [PMID: 34137767 DOI: 10.1039/d1sm00343g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The shapes of colloidal particles are crucial to self-assembled superstructures. Understanding the relationship between the shapes of building blocks and the resulting crystal structures is an important fundamental question. Here, we demonstrate that, by using particles whose shape interpolates between a flat disc and a sphere, not only are self-assembled superstructures but also their orientations sensitively dependent on the particle shape. By changing the shape gradually from a flat disc to a spherical shape, a crystal sequence from orientationally ordered crystals to orientationally disordered crystals with frozen and more free rotations are found. The latter two phases are identified as a glassy crystal and a plastic crystal, respectively. By combining theoretical model calculations, the formed crystal structures and the occurring transitions are found to be dictated by the interplay between particle shape and particle-particle interaction as well as particle-wall interaction. In particular, for quasi-spherical shapes, when the strong attraction dominates, a glassy crystal forms, or otherwise a plastic crystal forms. These results demonstrate that the interplay between the particle shape and the interaction can be used to tune crystallization and further fabricate colloid-based new structured and dynamic materials.
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Affiliation(s)
- Jiawei Lu
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China. and University of Chinese Academy of Sciences, Beijing, 100149, China
| | - Xiangyu Bu
- School of Science, Beijing Jiaotong University, Beijing, 100044, China
| | - Xinhua Zhang
- School of Science, Beijing Jiaotong University, Beijing, 100044, China
| | - Bing Liu
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China. and University of Chinese Academy of Sciences, Beijing, 100149, China
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22
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Han Y, Harris J, Walton J, Majumdar A. Tailored nematic and magnetization profiles on two-dimensional polygons. Phys Rev E 2021; 103:052702. [PMID: 34134325 DOI: 10.1103/physreve.103.052702] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 04/07/2021] [Indexed: 11/07/2022]
Abstract
We study dilute suspensions of magnetic nanoparticles in a nematic host, on two-dimensional polygons. These systems are described by a nematic order parameter and a spontaneous magnetization, in the absence of any external fields. We study the stable states in terms of stable critical points of an appropriately defined free energy, with a nemato-magnetic coupling energy. We numerically study the interplay between the shape of the regular polygon, the size of the polygon, and the strength of the nemato-magnetic coupling for the multistability of this prototype system. Our notable results include (1) the coexistence of stable states with domain walls and stable interior and boundary defects, (2) the suppression of multistability for positive nemato-magnetic coupling, and (3) the enhancement of multistability for negative nemato-magnetic coupling.
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Affiliation(s)
- Yucen Han
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow, G1 1XQ, United Kingdom
| | - Joseph Harris
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow, G1 1XQ, United Kingdom
| | - Joshua Walton
- School of Mathematics and Statistics, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Apala Majumdar
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow, G1 1XQ, United Kingdom
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23
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Vats A, Banerjee V, Puri S. Domain growth in ferronematics: slaved coarsening, emergent morphologies and growth laws. SOFT MATTER 2021; 17:2659-2674. [PMID: 33533368 DOI: 10.1039/d0sm01888k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ferronematics (FNs) are suspensions of magnetic nanoparticles in nematic liquid crystals (NLCs). They have attracted much experimental attention, and are of great interest both scientifically and technologically. There are very few theoretical studies of FNs, even in equilibrium. In this paper, we study the non-equilibrium phenomenon of domain growth after a thermal quench (or coarsening) in this coupled system. Our modeling is based on coupled time-dependent Ginzburg-Landau (TDGL) equations for two order parameters: the LC tensor order parameter Q, and the magnetization M. We consider both shallow and deep quenches from a high-temperature disordered phase. The system coarsens by the collision and annihilation of topological defects. We focus on slaved coarsening, where a disordered Q (or M) field is driven to coarsen by an ordered M (or Q) field. We present detailed results for the morphologies and growth laws, which exhibit unusual features purely due to the magneto-nematic coupling. To the best of our knowledge, this is the first study of non-equilibrium phenomena in FNs.
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Affiliation(s)
- Aditya Vats
- Department of Physics, Indian Institute of Technology Delhi, New Delhi - 110016, India
| | - Varsha Banerjee
- Department of Physics, Indian Institute of Technology Delhi, New Delhi - 110016, India
| | - Sanjay Puri
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi - 110067, India.
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24
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Garbovskiy Y. Conventional and unconventional ionic phenomena in tunable soft materials made of liquid crystals and nanoparticles. NANO EXPRESS 2021. [DOI: 10.1088/2632-959x/abe652] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
A great variety of tunable multifunctional materials can be produced by combining nanoparticles and liquid crystals. Typically, the tunability of such soft nanocomposites is achieved via external electric fields resulting in the field-induced reorientation of liquid crystals. This reorientation can be altered by ions normally present in liquid crystals in small quantities. In addition, nanomaterials dispersed in liquid crystals can also affect the behavior of ions. Therefore, an understanding of ionic phenomena in liquid crystals doped with nanoparticles is essential for future advances in liquid crystal-aided nanoscience and nanotechnology. This paper provides an overview of the ionic effects observed in liquid crystals doped with nanomaterials. An introduction to liquid crystals is followed by a brief overview of nanomaterials in liquid crystals. After giving a basic description of ions in liquid crystals and experimental methods to measure them, a wide range of ionic phenomena in liquid crystals doped with different types of nanomaterials is discussed. After that, both existing and emerging applications of tunable soft materials made of liquid crystals and nanodopants are presented with an emphasis on the role of ionic effects in such systems. Finally, the discussion of unsolved problems and future research directions completes the review.
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25
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Draude AP, Dierking I. Thermotropic liquid crystals with low-dimensional carbon allotropes. NANO EXPRESS 2021. [DOI: 10.1088/2632-959x/abdf2d] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Abstract
As display devices based on liquid crystals have matured over the last decades, liquid crystal research has shifted its priorities in slightly different directions, such as sensors, photonics, nanotechnology and even more biologically related fields like drug delivery. This implied a change of emphasis in the development of novel materials, of which a completely new class of liquid crystal based composites emerged, that of nanoparticle-dispersed liquid crystals. The underlying ideas were to add functionality, while maintaining switchability, and the exploitation of liquid crystal self-organisation to build hierarchical nanostructures. Of particular interest for applications are dispersions of carbon nanomaterials, such as fullerenes, nanotubes and the graphene variants, due to their interactions with conventional liquid crystals. While such systems have been investigated for the past two decades, we concentrate in this review on the effects of dimensionality of the dispersed carbon nanoparticles, which goes hand in hand with the more recent developments in this field. Examples are the doping of 0D fullerenes in liquid crystals and implications for Blue Phase stability, or 1D nanotubes in nematic and ferroelectric liquid crystals, questions of dispersibility and applications as alignment media in ITO-free devices. Graphene (2D) and especially graphene oxide are mainly investigated for their formation of lyotropic liquid crystals. We here discuss the more recent aspects of dispersion in thermotropics.
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26
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Qu N, Luo Z, Zhao S, Liu B. Frame-Guided Synthesis of Polymeric Colloidal Discs. J Am Chem Soc 2021; 143:1790-1797. [PMID: 33467847 DOI: 10.1021/jacs.0c08627] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Anisotropic colloidal particles are important building blocks for the studies of self-assembly, which are visualized models for basic research and can be used to construct structured materials. Discs are one of the most typical anisotropic colloids; however, the synthesis of monodisperse colloidal discs with well-defined shape remains a challenge. Here we report a novel strategy for synthesizing polymeric discs based on frame-guided droplet shrinkage. This was realized by creating frame/liquid core/shell rings and utilizing the shrinking instability of the liquid rings. The resulting disc's shape parameters are tunable. The method is general, is not limited to specific polymers, solvents, and frames, and therefore has the potential to afford a variety of polymer discs. We also demonstrate the possibility of tuning the surface chemistry of the discs through surface-initiated polymerization. The frame-guided droplet shrinkage method opens up a new way to design and fabricate colloidal particles.
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Affiliation(s)
- Na Qu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100149, China
| | - Zhang Luo
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100149, China
| | - Shuping Zhao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100149, China
| | - Bing Liu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100149, China
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27
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Cao W, Yin S, Plank M, Chumakov A, Opel M, Chen W, Kreuzer LP, Heger JE, Gallei M, Brett CJ, Schwartzkopf M, Eliseev AA, Anokhin EO, Trusov LA, Roth SV, Müller-Buschbaum P. Spray-Deposited Anisotropic Ferromagnetic Hybrid Polymer Films of PS- b-PMMA and Strontium Hexaferrite Magnetic Nanoplatelets. ACS APPLIED MATERIALS & INTERFACES 2021; 13:1592-1602. [PMID: 33355441 DOI: 10.1021/acsami.0c19595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Spray deposition is a scalable and cost-effective technique for the fabrication of magnetic hybrid films containing diblock copolymers (DBCs) and magnetic nanoparticles. However, it is challenging to obtain spray-deposited anisotropic magnetic hybrid films without using external magnetic fields. In the present work, spray deposition is applied to prepare perpendicular anisotropic magnetic hybrid films by controlling the orientation of strontium hexaferrite nanoplatelets inside ultra-high-molecular-weight DBC polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) films. During spray deposition, the evolution of DBC morphology and the orientation of magnetic nanoplatelets are monitored with in situ grazing-incidence small-angle X-ray scattering (GISAXS). For reference, a pure DBC film without nanoplatelets is deposited with the same conditions. Solvent-controlled magnetic properties of the hybrid film are proven with solvent vapor annealing (SVA) applied to the final deposited magnetic films. Obvious changes in the DBC morphology and nanoplatelet localization are observed during SVA. The superconducting quantum interference device data show that ferromagnetic hybrid polymer films with high coercivity can be achieved via spray deposition. The hybrid films show a perpendicular magnetic anisotropy before SVA, which is strongly weakened after SVA. The spray-deposited hybrid films appear highly promising for potential applications in magnetic data storage and sensors.
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Affiliation(s)
- Wei Cao
- Physik-Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Shanshan Yin
- Physik-Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Martina Plank
- Ernst-Berl-Institute for Technical and Macromolecular Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany
| | - Andrei Chumakov
- Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany
| | - Matthias Opel
- Bayerische Akademie der Wissenschaften, Walther-Meissner-Institut, Walther-Meissner-Straße 8, 85748 Garching, Germany
| | - Wei Chen
- Physik-Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Lucas P Kreuzer
- Physik-Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Julian E Heger
- Physik-Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Markus Gallei
- Chair in Polymer Chemistry, Saarland University, Campus C4 2, 66123 Saarbrücken, Germany
| | - Calvin J Brett
- Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany
- Department of Engineering Mechanics, KTH Royal Institute of Technology, Teknikringen 8, SE-100 44 Stockholm, Sweden
- Wallenberg Wood Science Center, KTH Royal Institute of Technology, Teknikringen 56-58, SE-100 44 Stockholm, Sweden
| | | | - Artem A Eliseev
- Department of Chemistry, Moscow State University, 119991 Moscow, Russia
| | - Evgeny O Anokhin
- Department of Materials Science, Moscow State University, 119991 Moscow, Russia
| | - Lev A Trusov
- Department of Chemistry, Moscow State University, 119991 Moscow, Russia
| | - Stephan V Roth
- Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany
- Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Teknikringen 56-58, SE-100 44 Stockholm, Sweden
| | - Peter Müller-Buschbaum
- Physik-Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, 85748 Garching, Germany
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28
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Abstract
Abstract
The integration of nanoparticles with magnetic, ferroelectric or semiconducting properties into liquid crystals (LCs) has attracted great interest both for fundamental investigations and for technological applications. Here, an overview of hybrid materials based on magnetic nanoparticles (MNPs) and thermotropic LCs is given. After a general introduction to thermotropic LCs and LC-MNP hybrid materials, various preparation methods established by us are presented. The synthesis of shape-(an)isotropic MNPs, their functionalization by tailored (pro)mesogenic ligands with linear or dendritic structures and their integration into LC hosts are discussed. The characterization of the MNPs, (pro)mesogenic ligands and resulting MNP-LC hybrid materials is described to show the influence of MNP functionalization on the MNP-LC interactions including aspects such as colloidal stability and structuring in the LC host. Overall, we show that the physical properties of the hybrid material are significantly influenced not only by the MNPs (i.e., their size, shape and composition) but also by their surface properties (i.e., the structure of the (pro)mesogenic ligands).
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Affiliation(s)
- Martin Hähsler
- Institute of Catalysis Research and Technology , Karlsruhe Institute of Technology , Postfach 3640 , 76021 Karlsruhe , Germany
- Institute of Inorganic Chemistry , Ruprecht-Karls University Heidelberg , Im Neuenheimer Feld 270 , 69120 Heidelberg , Germany
| | - Ingo Appel
- Institute of Catalysis Research and Technology , Karlsruhe Institute of Technology , Postfach 3640 , 76021 Karlsruhe , Germany
- Institute of Inorganic Chemistry , Ruprecht-Karls University Heidelberg , Im Neuenheimer Feld 270 , 69120 Heidelberg , Germany
| | - Silke Behrens
- Institute of Catalysis Research and Technology , Karlsruhe Institute of Technology , Postfach 3640 , 76021 Karlsruhe , Germany
- Institute of Inorganic Chemistry , Ruprecht-Karls University Heidelberg , Im Neuenheimer Feld 270 , 69120 Heidelberg , Germany
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29
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Lee YH, Shi W, Yang Y, Kao YC, Lee HK, Chu R, Pang YL, Lay CL, Li S, Ling XY. Modulating Orientational Order to Organize Polyhedral Nanoparticles into Plastic Crystals and Uniform Metacrystals. Angew Chem Int Ed Engl 2020; 59:21183-21189. [PMID: 32767617 DOI: 10.1002/anie.202009941] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Indexed: 01/11/2023]
Abstract
In nanoparticle self-assembly, the current lack of strategy to modulate orientational order creates challenges in isolating large-area plastic crystals. Here, we achieve two orientationally distinct supercrystals using one nanoparticle shape, including plastic crystals and uniform metacrystals. Our approach integrates multi-faceted Archimedean polyhedra with molecular-level surface polymeric interactions to tune nanoparticle orientational order during self-assembly. Experiments and simulations show that coiled surface polymer chains limit interparticle interactions, creating various geometrical configurations among Archimedean polyhedra to form plastic crystals. In contrast, brush-like polymer chains enable molecular interdigitation between neighboring particles, favoring consistent particle configurations and result in uniform metacrystals. Our strategy enhances supercrystal diversity for polyhedra comprising multiple nondegenerate facets.
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Affiliation(s)
- Yih Hong Lee
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Wenxiong Shi
- State Key Laboratory of Separation Membranes and Membrane Processes, School of Materials Science and Engineering, Tiangong University, Tianjin, 300387, P. R. China
| | - Yijie Yang
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Ya-Chuan Kao
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Hiang Kwee Lee
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Rongrong Chu
- State Key Laboratory of Separation Membranes and Membrane Processes, School of Materials Science and Engineering, Tiangong University, Tianjin, 300387, P. R. China
| | - Yee Ling Pang
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Chee Leng Lay
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore.,Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, #08-03, Singapore, 138634, Singapore
| | - Shuzhou Li
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Xing Yi Ling
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
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30
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Lee YH, Shi W, Yang Y, Kao Y, Lee HK, Chu R, Pang YL, Lay CL, Li S, Ling XY. Modulating Orientational Order to Organize Polyhedral Nanoparticles into Plastic Crystals and Uniform Metacrystals. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009941] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Yih Hong Lee
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Wenxiong Shi
- State Key Laboratory of Separation Membranes and Membrane Processes School of Materials Science and Engineering Tiangong University Tianjin 300387 P. R. China
| | - Yijie Yang
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Ya‐Chuan Kao
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Hiang Kwee Lee
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Rongrong Chu
- State Key Laboratory of Separation Membranes and Membrane Processes School of Materials Science and Engineering Tiangong University Tianjin 300387 P. R. China
| | - Yee Ling Pang
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Chee Leng Lay
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
- Institute of Materials Research and Engineering Agency for Science, Technology and Research (A*STAR) 2 Fusionopolis Way, Innovis, #08-03 Singapore 138634 Singapore
| | - Shuzhou Li
- School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
| | - Xing Yi Ling
- Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
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31
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Kuciakowski J, Kmita A, Lachowicz D, Wytrwal-Sarna M, Pitala K, Lafuerza S, Koziej D, Juhin A, Sikora M. Selective magnetometry of superparamagnetic iron oxide nanoparticles in liquids. NANOSCALE 2020; 12:16420-16426. [PMID: 32744559 DOI: 10.1039/d0nr02866e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We show that the properties of superparamagnetic iron oxide nanoparticles suspended in liquids can be effectively studied using Magnetic Circular Dichroism in Resonant Inelastic X-ray Scattering. Analysis of the spectral shape and magnetic contrast produced by this experiment enables an assessment of the site distribution and magnetic state of metal ions in the spinel phase. The selective magnetization profile of particles as derived from the field dependence of dichroism empowers an estimation of particle size distribution. Furthermore, the new proposed methodology discriminates sizes that are below the detection limits of X-ray and light scattering probes and that are difficult to spot in TEM.
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Affiliation(s)
- Juliusz Kuciakowski
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, Al. Mickiewicza 30, 30-059 Krakow, Poland. and AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Al. Mickiewicza 30, 30-059 Krakow, Poland
| | - Angelika Kmita
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, Al. Mickiewicza 30, 30-059 Krakow, Poland.
| | - Dorota Lachowicz
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, Al. Mickiewicza 30, 30-059 Krakow, Poland.
| | - Magdalena Wytrwal-Sarna
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, Al. Mickiewicza 30, 30-059 Krakow, Poland.
| | - Krzysztof Pitala
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, Al. Mickiewicza 30, 30-059 Krakow, Poland. and AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Al. Mickiewicza 30, 30-059 Krakow, Poland
| | - Sara Lafuerza
- European Synchrotron Radiation Facility, CS40220, 38043 Grenoble Cedex 9, France
| | - Dorota Koziej
- Institute of Nanostructure- and Solid State Physics, Center for Hybrid Nanostructures, University of Hamburg, Luruper Chaussee 149, 22607 Hamburg, Germany
| | - Amélie Juhin
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, UMR CNRS 7590, Muséum National d'Histoire Naturelle, 4 Place Jussieu, 75005 Paris, France
| | - Marcin Sikora
- AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, Al. Mickiewicza 30, 30-059 Krakow, Poland.
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32
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Rosenberg M, Gregorin Ž, Boštjančič PH, Sebastián N, Lisjak D, Kantorovich SS, Mertelj A, Sánchez PA. The influence of polydispersity on the structural properties of the isotropic phase of magnetic nanoplatelets. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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33
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Dierking I, Yoshida S, Kelly T, Pitcher W. Liquid crystal-ferrofluid emulsions. SOFT MATTER 2020; 16:6021-6031. [PMID: 32555906 DOI: 10.1039/d0sm00880j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Despite the development of the brilliant flat-panel TVs and computer screens that we all use on a daily basis, liquid crystals are far from being exhausted as a topic of research. Novel effects, new, modern, self-organized materials, and a range of applications are being developed, which are on the borderline between nanotechnology and soft condensed matter, and which use liquid crystals as a vehicle to study fundamental physical questions, all the way to mimicking nature and life. In this perspective article we will introduce an illustrative example, which will draw on a range of non-display aspects in liquid crystal research which have increasingly gained interest over the past years, namely self-organization of liquid crystals, colloidal ordering of magnetic nanoparticles, topological defects, and biological structures.
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Affiliation(s)
- Ingo Dierking
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Susumu Yoshida
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Thomas Kelly
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - William Pitcher
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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34
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Lisjak D, Hribar Boštjančič P, Mertelj A, Mavrič A, Valant M, Kovač J, Hudelja H, Kocjan A, Makovec D. Formation of Fe(III)-phosphonate Coatings on Barium Hexaferrite Nanoplatelets for Porous Nanomagnets. ACS OMEGA 2020; 5:14086-14095. [PMID: 32566875 PMCID: PMC7301540 DOI: 10.1021/acsomega.0c01597] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
Amorphous coatings formed with mono-, di-, and tetra-phosphonic acids on barium hexaferrite (BHF) nanoplatelets using various synthesis conditions. The coatings, synthesized in water with di- or tetra-phosphonic acids, were thicker than that could be expected from the ligand size and the surface coverage, as determined by thermogravimetric analysis. Here, we propose a mechanism for coating formation based on direct evidence of the surface dissolution/precipitation of the BHF nanoplatelets. The partial dissolution of the nanoplatelets was observed with atomic-resolution scanning transmission electron microscopy, and the released Fe(III) ions were detected with energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy in amorphous coating. The strong chemical interaction between the surface Fe(III) ions with phosphonic ligands induces the dissolution of BHF nanoplatelets and the consequent precipitation of the Fe(III)-phosphonates that assemble into a porous coating. The so-obtained porous nanomagnets are highly responsive to a very weak magnetic field (in the order of Earth's magnetic field) at room temperature, which is a major advantage over the classic mesoporous nanomaterials and metal-organo-phosphonic frameworks with only a weak magnetic response at a few kelvins. The combination of porosity with the intrinsic magneto-crystalline anisotropy of BHF can be exploited, for example, as sorbents for heavy metals from contaminated water.
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Affiliation(s)
- Darja Lisjak
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
| | - Patricija Hribar Boštjančič
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
- Jožef
Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia
| | - Alenka Mertelj
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
| | - Andraž Mavrič
- University
of Nova Gorica, Vipavska 13, 5000 Nova Gorica, Slovenia
- Institute
of Fundamental and Frontier Sciences, University
of Electronic Science and Technology of China, Chengdu 610054, China
| | - Matjaz Valant
- University
of Nova Gorica, Vipavska 13, 5000 Nova Gorica, Slovenia
- Institute
of Fundamental and Frontier Sciences, University
of Electronic Science and Technology of China, Chengdu 610054, China
| | - Janez Kovač
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
| | - Hermina Hudelja
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
- Jožef
Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia
| | - Andraž Kocjan
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
| | - Darko Makovec
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
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35
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First-principles experimental demonstration of ferroelectricity in a thermotropic nematic liquid crystal: Polar domains and striking electro-optics. Proc Natl Acad Sci U S A 2020; 117:14021-14031. [PMID: 32522878 PMCID: PMC7322023 DOI: 10.1073/pnas.2002290117] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report the experimental determination of the structure and response to applied electric field of the lower-temperature nematic phase of the previously reported calamitic compound 4-[(4-nitrophenoxy)carbonyl]phenyl2,4-dimethoxybenzoate (RM734). We exploit its electro-optics to visualize the appearance, in the absence of applied field, of a permanent electric polarization density, manifested as a spontaneously broken symmetry in distinct domains of opposite polar orientation. Polarization reversal is mediated by field-induced domain wall movement, making this phase ferroelectric, a 3D uniaxial nematic having a spontaneous, reorientable polarization locally parallel to the director. This polarization density saturates at a low temperature value of ∼6 µC/cm2, the largest ever measured for a fluid or glassy material. This polarization is comparable to that of solid state ferroelectrics and is close to the average value obtained by assuming perfect, polar alignment of molecular dipoles in the nematic. We find a host of spectacular optical and hydrodynamic effects driven by ultralow applied field (E ∼ 1 V/cm), produced by the coupling of the large polarization to nematic birefringence and flow. Electrostatic self-interaction of the polarization charge renders the transition from the nematic phase mean field-like and weakly first order and controls the director field structure of the ferroelectric phase. Atomistic molecular dynamics simulation reveals short-range polar molecular interactions that favor ferroelectric ordering, including a tendency for head-to-tail association into polar, chain-like assemblies having polar lateral correlations. These results indicate a significant potential for transformative, new nematic physics, chemistry, and applications based on the enhanced understanding, development, and exploitation of molecular electrostatic interaction.
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36
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Bisht K, Wang Y, Banerjee V, Majumdar A. Tailored morphologies in two-dimensional ferronematic wells. Phys Rev E 2020; 101:022706. [PMID: 32168669 DOI: 10.1103/physreve.101.022706] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/04/2020] [Indexed: 11/07/2022]
Abstract
We focus on a dilute uniform suspension of magnetic nanoparticles in a nematic-filled micron-sized shallow well with tangent boundary conditions as a paradigm system with two coupled order parameters. This system exhibits spontaneous magnetization without magnetic fields. We numerically obtain the stable nematic and associated magnetization morphologies, induced purely by the geometry, the boundary conditions, and the coupling between the magnetic nanoparticles and the host nematic medium. Our most striking observations pertain to domain walls in the magnetization profile, whose location can be manipulated by the coupling and material properties, and stable interior and boundary nematic defects, whose location and multiplicity can be tailored by the coupling too. These tailored morphologies are not accessible in uncoupled systems and can be used for multistable systems with singularities and stable interfaces.
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Affiliation(s)
- Konark Bisht
- Department of Physics, Indian Institute of Technology, Delhi, Hauz Khas 110016, New Delhi, India
| | - Yiwei Wang
- Department of Applied Mathematics, Illinois Institute of Technology, Chicago, Illinois 60616, USA
| | - Varsha Banerjee
- Department of Physics, Indian Institute of Technology, Delhi, Hauz Khas 110016, New Delhi, India
| | - Apala Majumdar
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow G1 1XQ, United Kingdom.,Department of Mathematical Sciences, University of Bath, Bath BA2 7AY, United Kingdom
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37
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Petrov DA. Molecular-statistical theory of ferromagnetic liquid crystal suspensions. Phys Rev E 2020; 101:030701. [PMID: 32289958 DOI: 10.1103/physreve.101.030701] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/03/2020] [Indexed: 11/07/2022]
Abstract
A tensor variant of molecular-statistical theory is developed, within the framework of which it is possible to describe the appearance of spontaneous magnetization of anisotropic ferromagnetic nanoparticles dispersed in a nematic liquid crystal. Along with the tensor order parameters characterizing the orientational ordering of the liquid crystal and dispersed anisometric particles, the vector order parameter determining the magnetization of the ensemble of particles is additionally taken into account. A comparison between the previously known phenomenological theories of ferronematics and the proposed molecular-statistical theory is made. Phase diagrams of the suspension are constructed and the mean-field theory parameters are calculated on the basis of experimental data available in the literature.
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Affiliation(s)
- Danil A Petrov
- Physics of Phase Transitions Department, Perm State University, Bukirev St. 15, 614990 Perm, Russia
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38
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Huang X, Wang L, Zhao J, Liu C, Zhou F, Xu Z, Pei H. Fabrication and application of flexible rectangular microtubes. POLYM-PLAST TECH MAT 2020. [DOI: 10.1080/25740881.2019.1708104] [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]
Affiliation(s)
- Xing Huang
- Institute of Process Equipment, College of Energy Engineering, Zhejiang University, Hangzhou, China
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Lei Wang
- Institute of Process Equipment, College of Energy Engineering, Zhejiang University, Hangzhou, China
| | - Jianxiang Zhao
- Institute of Process Equipment, College of Energy Engineering, Zhejiang University, Hangzhou, China
| | - Cong Liu
- Institute of Process Equipment, College of Energy Engineering, Zhejiang University, Hangzhou, China
| | - Fanghao Zhou
- Institute of Process Equipment, College of Energy Engineering, Zhejiang University, Hangzhou, China
| | - Zhongbin Xu
- Institute of Process Equipment, College of Energy Engineering, Zhejiang University, Hangzhou, China
| | - Hao Pei
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
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39
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Makovec D, Dražić G, Gyergyek S, Lisjak D. A new polymorph of strontium hexaferrite stabilized at the nanoscale. CrystEngComm 2020. [DOI: 10.1039/d0ce01111h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
During hydrothermal synthesis the magnetoplumbite strontium-ferrite nanoplatelets form via the growth of primary discoid nanoplatelets with a new, incredibly complex hexagonal structure.
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Affiliation(s)
- D. Makovec
- Department for Materials Synthesis
- Jožef Stefan Institute
- SI-1000 Ljubljana
- Slovenia
| | - G. Dražić
- Department for Materials Chemistry
- National Institute of Chemistry
- SI-1000 Ljubljana
- Slovenia
| | - S. Gyergyek
- Department for Materials Synthesis
- Jožef Stefan Institute
- SI-1000 Ljubljana
- Slovenia
| | - D. Lisjak
- Department for Materials Synthesis
- Jožef Stefan Institute
- SI-1000 Ljubljana
- Slovenia
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40
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Magnetic Ordering in Systems of Identical Particles with an Arbitrary Spin. CHEMOSENSORS 2019. [DOI: 10.3390/chemosensors7040054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Wigner–Eckart theorem is used for considering the collective effects related to ordering spins in systems of identical particles in ferro- and antiferromagnetic electronic systems, as well as magnetic effects that occur in high spin systems. The Hamiltonian, written in the spin representation in the form obtained by Heisenberg, Dirac, and van Vleck used to describe spin ordering in systems of particles with spin ½, is not appropriate for a description of particle systems with a spin different from ½. “High” spin particles in the spin representation need other forms of the Hamiltonian of the exchange interaction in the spin representation. The Hamiltonian for high-spin particles has been developed from the first principles, and the effects of magnetic ordering in systems of identical particles with arbitrary spin are considered in this review. An effect of giant negative magnetoresistance in the Indium antimonide has been interpreted from the exchange contribution of a high spin heavy holes point of view.
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41
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Bisht K, Banerjee V, Milewski P, Majumdar A. Magnetic nanoparticles in a nematic channel: A one-dimensional study. Phys Rev E 2019; 100:012703. [PMID: 31499772 DOI: 10.1103/physreve.100.012703] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Indexed: 11/07/2022]
Abstract
We study a dilute suspension of magnetic nanoparticles in a nematic-filled channel and how the spatial magnetization M can be tailored by the nematic anisotropy. We study the spatial configurations as stable critical points of a generalized phenomenological energy for a dilute ferronematic in the absence of external magnetic fields. We show how spatial inhomogeneities in the equilibrium nematic profile, induced by confinement and boundary effects, generate nonzero spatially inhomogeneous magnetization profiles in the system. Depending on the magnetonematic coupling energy, M can either follow the nematic profile for large coupling or exhibit distinct polydomain structures separated by defect lines for weak coupling and low temperatures. Some exact solutions for prototypical situations are also obtained.
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Affiliation(s)
- Konark Bisht
- Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Varsha Banerjee
- Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Paul Milewski
- Department of Mathematical Sciences, University of Bath, Bath BA2 7AY, United Kingdom
| | - Apala Majumdar
- Department of Mathematical Sciences, University of Bath, Bath BA2 7AY, United Kingdom
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42
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Tomczyk E, Promiński A, Bagiński M, Górecka E, Wójcik M. Gold Nanoparticles Thin Films with Thermo- and Photoresponsive Plasmonic Properties Realized with Liquid-Crystalline Ligands. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1902807. [PMID: 31348618 DOI: 10.1002/smll.201902807] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/05/2019] [Indexed: 05/13/2023]
Abstract
Robust synthesis of large-scale self-assembled nanostructures with long-range organization and a prominent response to external stimuli is critical to their application in functional plasmonics. Here, the first example of a material made of liquid crystalline nanoparticles which exhibits UV-light responsive surface plasmon resonance in a condensed state is presented. To obtain the material, metal cores are grafted with two types of organic ligands. A promesogenic derivative softens the system and induces rich liquid crystal phase polymorphism. Second, an azobenzene derivative endows nanoparticles with photoresponsive properties. It is shown that nanoparticles covered with a mixture of these ligands assemble into long-range ordered structures which exhibit a novel dual-responsivity. The structure and plasmonic properties of the assemblies can be controlled by a change in temperature as well as by UV-light irradiation. These results present an efficient way to obtain bulk quantities of self-assembled nanostructured materials with stability that is unattainable by alternative methods such as matrix-assisted or DNA-mediated organization.
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Affiliation(s)
- Ewelina Tomczyk
- Laboratory of Organic Nanomaterials and Biomolecules, Faculty of Chemistry, University of Warsaw, Pasteura 1 Street, 02-093, Warsaw, Poland
| | - Aleksander Promiński
- Laboratory of Organic Nanomaterials and Biomolecules, Faculty of Chemistry, University of Warsaw, Pasteura 1 Street, 02-093, Warsaw, Poland
| | - Maciej Bagiński
- Laboratory of Organic Nanomaterials and Biomolecules, Faculty of Chemistry, University of Warsaw, Pasteura 1 Street, 02-093, Warsaw, Poland
| | - Ewa Górecka
- Laboratory of Physicochemistry of Dielectrics and Magnetics, Faculty of Chemistry, University of Warsaw, wirki i Wigury 101 Street, 02-089, Warsaw, Poland
| | - Michał Wójcik
- Laboratory of Organic Nanomaterials and Biomolecules, Faculty of Chemistry, University of Warsaw, Pasteura 1 Street, 02-093, Warsaw, Poland
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43
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Geier IS, Wandrei SM, Skutnik RA, Schoen M. Molecular theory of a ferromagnetic nematic liquid crystal. Phys Rev E 2019; 100:022702. [PMID: 31574629 DOI: 10.1103/physreve.100.022702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Indexed: 06/10/2023]
Abstract
We employ a version of classical density functional theory to study the phase behavior of a simple model liquid crystal in an external field. The uniaxially symmetric molecules have a spherically symmetric core with superimposed orientation-dependent attractions. The interaction between the cores consists of a hard-sphere repulsion plus an isotropic square-well attraction. The anisotropic part of the interaction potential allows for the formation of a uniaxially symmetric nematic phase. The orientation of the molecules couples to an external polar field. The external field is capable of rotating the nematic director n[over ̂] in the x-z plane. The field is also capable of changing the topology of the phase diagram in that it suppresses the phase coexistence between an isotropic liquid and a nematic phase observed in the absence of the field. We study the transition from an unpolar to a polar nematic phase in terms of the orientation-distribution function (odf), nematic and polar order parameters, and components of n[over ̂]. If represented suitably the odf allows us to study orientational changes during the switching process between nonpolar and polar nematic phases. We also give a simple argument that explains why nematic order is lost whereas polar order persists up to the gas-liquid critical point along the coexistence curve. We also discuss the relevance of our theory for future experimental studies.
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Affiliation(s)
- Immanuel S Geier
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Fakultät für Mathematik und Naturwissenschaften, Technische Universität Berlin, Straße des 17. Juni 115, 10623 Berlin, Germany
| | - Stefanie M Wandrei
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Fakultät für Mathematik und Naturwissenschaften, Technische Universität Berlin, Straße des 17. Juni 115, 10623 Berlin, Germany
| | - Robert A Skutnik
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Fakultät für Mathematik und Naturwissenschaften, Technische Universität Berlin, Straße des 17. Juni 115, 10623 Berlin, Germany
| | - Martin Schoen
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Fakultät für Mathematik und Naturwissenschaften, Technische Universität Berlin, Straße des 17. Juni 115, 10623 Berlin, Germany
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
- Department of Chemical and Biomolecular Engineering, Engineering Building I, Box 7905, North Carolina State University, 911 Partners Way, Raleigh, North Carolina 27695, USA
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44
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Mertelj A, Lampret B, Lisjak D, Klepp J, Kohlbrecher J, Čopič M. Evolution of nematic and ferromagnetic ordering in suspensions of magnetic nanoplatelets. SOFT MATTER 2019; 15:5412-5420. [PMID: 31241639 DOI: 10.1039/c9sm00949c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Suspensions of magnetic nanoplatelets in isotropic solvents are very interesting examples of ferrofluids. It has been shown that above a certain concentration ΦNI such suspensions form a ferromagnetic nematic phase, which makes this system a unique example of a dipolar fluid. The formation of a nematic phase is driven by anisotropic electrostatic and long-range dipolar magnetic interactions. Here, we present studies of the evolution of short range positional and orientational magnetic order in suspensions with volume fractions below and above ΦNI, using small angle neutron scattering (SANS). The results show that in the absence of an external magnetic field, short range positional and orientational order already exist at relatively low volume fractions. Polarized SANS revealed that the contribution of ferromagnetic ordering to the formation of the nematic phase is significant. The ferromagnetic correlations can be qualitatively explained by a simple model, which takes into account anisotropic screened electrostatic and dipolar magnetic interactions.
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Affiliation(s)
| | - Borut Lampret
- J. Stefan Institute, SI-1000 Ljubljana, Slovenia and Faculty of Mathematics and Physics, University of Ljubljana, Slovenia
| | - Darja Lisjak
- J. Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Jürgen Klepp
- Faculty of Physics, University of Vienna, A-1090 Vienna, Austria
| | - Joachim Kohlbrecher
- Laboratory for Neutron Scattering and Imaging, PSI, CH-5232 Villigen PSI, Switzerland
| | - Martin Čopič
- J. Stefan Institute, SI-1000 Ljubljana, Slovenia
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45
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Hu J, Gorsak T, Martín Rodríguez E, Calle D, Muñoz‐Ortiz T, Jaque D, Fernández N, Cussó L, Rivero F, Aguilar Torres R, García Solé J, Mertelj A, Makovec D, Desco M, Lisjak D, Alfonso F, Sanz‐Rodríguez F, Ortgies DH. Magnetic Nanoplatelets for High Contrast Cardiovascular Imaging by Magnetically Modulated Optical Coherence Tomography. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900071] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Jie Hu
- Xiamen Institute of Rare-earth Materials, Haixi InstitutesChinese Academy of Sciences 258 Duishanxiheng Road, Jimei District Xiamen 361024, Fujian China
| | - Tanja Gorsak
- Jožef Stefan InstituteDepartment for Materials Synthesis Ljubljana 1000 Slovenia
- Jožef Stefan International Postgraduate School Ljubljana 1000 Slovenia
| | - Emma Martín Rodríguez
- Fluorescence Imaging Group, Departamento de Física AplicadaUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
- Nanobiology GroupInstituto Ramón y Cajal de Investigación Sanitaria IRYCIS Ctra. Colmenar km. 9.100 Madrid 28034 Spain
| | - Daniel Calle
- Instituto de Investigación Sanitaria Gregorio Marañón Madrid 28007 Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Madrid 28029 Spain
| | - Tamara Muñoz‐Ortiz
- Fluorescence Imaging Group Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
| | - Daniel Jaque
- Fluorescence Imaging Group Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
- Nanobiology GroupInstituto Ramón y Cajal de Investigación Sanitaria IRYCIS Ctra. Colmenar km. 9.100 Madrid 28034 Spain
| | - Nuria Fernández
- Fluorescence Imaging Group, Departamento de Fisiología Facultad de Medicina, Avda. Arzobispo Morcillo 2Universidad Autónoma de Madrid 28029 Madrid Spain
| | - Lorena Cussó
- Departamento de Bioingeniería e Ingeniería AeroespacialUniversidad Carlos III de Madrid 28911 Madrid Spain
- Instituto de Investigación Sanitaria Gregorio Marañón Madrid 28007 Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Madrid 28029 Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM) Madrid 28029 Spain
| | - Fernando Rivero
- Cardiology Department, Hospital Universitario de la Princesa, IIS-IPUniversidad Autónoma de Madrid Madrid 28006 Spain
| | - Río Aguilar Torres
- Cardiology Department, Hospital Universitario de la Princesa, IIS-IPUniversidad Autónoma de Madrid Madrid 28006 Spain
| | - José García Solé
- Fluorescence Imaging Group Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
| | - Alenka Mertelj
- Jožef Stefan Institute, Department for Complex Matter Ljubljana 1000 Slovenia
| | - Darko Makovec
- Jožef Stefan InstituteDepartment for Materials Synthesis Ljubljana 1000 Slovenia
| | - Manuel Desco
- Departamento de Bioingeniería e Ingeniería AeroespacialUniversidad Carlos III de Madrid 28911 Madrid Spain
- Instituto de Investigación Sanitaria Gregorio Marañón Madrid 28007 Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Madrid 28029 Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM) Madrid 28029 Spain
| | - Darja Lisjak
- Jožef Stefan InstituteDepartment for Materials Synthesis Ljubljana 1000 Slovenia
| | - Fernando Alfonso
- Cardiology Department, Hospital Universitario de la Princesa, IIS-IPUniversidad Autónoma de Madrid Madrid 28006 Spain
| | - Francisco Sanz‐Rodríguez
- Fluorescence Imaging Group, Departamento de BiologíaUniversidad Autónoma de Madrid Madrid 28049 Spain
| | - Dirk H. Ortgies
- Fluorescence Imaging Group Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
- Nanobiology GroupInstituto Ramón y Cajal de Investigación Sanitaria IRYCIS Ctra. Colmenar km. 9.100 Madrid 28034 Spain
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46
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Ji Y, Fan F, Xu S, Yu J, Chang S. Manipulation enhancement of terahertz liquid crystal phase shifter magnetically induced by ferromagnetic nanoparticles. NANOSCALE 2019; 11:4933-4941. [PMID: 30834911 DOI: 10.1039/c8nr09259a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ferromagnetic liquid crystals (FLCs), the suspensions of magnetic nanoparticles dispersed at different concentrations in liquid crystals (LCs), and their special magnetically induced birefringence characteristics have been investigated in the terahertz regime, mainly focusing on the interaction between magnetic cluster chains and LC molecules. We experimentally demonstrated the surface anchoring effect of the magnetic cluster chains on LC molecules in a mm-thick LC cell under an extremely weak external magnetic field (EMF), leading to a uniform anchoring arrangement of the LC molecules over the entire LC cell. Unlike pure 5CB LCs, the phase shift range of the FLCs at 1.45 THz up to π (no to ne or ne to no) can be achieved over the whole tunable range by simply changing the magnitude of the EMF without changing its direction, and the optical axis of LC molecules can be controlled to rotate by 90°, thereby realizing a tunable THz wave plate. This work provides a new way in the development of THz magneto-optic devices and phase devices.
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Affiliation(s)
- Yunyun Ji
- Institute of Modern Optics, Nankai University, Tianjin 300350, China.
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Zhou Z, Yang L, Gao J, Chen X. Structure-Relaxivity Relationships of Magnetic Nanoparticles for Magnetic Resonance Imaging. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1804567. [PMID: 30600553 PMCID: PMC6392011 DOI: 10.1002/adma.201804567] [Citation(s) in RCA: 201] [Impact Index Per Article: 40.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/17/2018] [Indexed: 05/17/2023]
Abstract
Magnetic nanoparticles (MNPs) have been extensively explored as magnetic resonance imaging (MRI) contrast agents. With the increasing complexity in the structure of modern MNPs, the classical Solomon-Bloembergen-Morgan and the outer-sphere quantum mechanical theories established on simplistic models have encountered limitations for defining the emergent phenomena of relaxation enhancement in MRI. Recent progress in probing MRI relaxivity of MNPs based on structural features at the molecular and atomic scales is reviewed, namely, the structure-relaxivity relationships, including size, shape, crystal structure, surface modification, and assembled structure. A special emphasis is placed on bridging the gaps between classical simplistic models and modern MNPs with elegant structural complexity. In the pursuit of novel MRI contrast agents, it is hoped that this review will spur the critical thinking for design and engineering of novel MNPs for MRI applications across a broad spectrum of research fields.
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Affiliation(s)
- Zijian Zhou
- † State Key Laboratory of Physical Chemistry of Solid Surfaces, The Key Laboratory for Chemical Biology of Fujian Province, and Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
- ‡ Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lijiao Yang
- † State Key Laboratory of Physical Chemistry of Solid Surfaces, The Key Laboratory for Chemical Biology of Fujian Province, and Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jinhao Gao
- † State Key Laboratory of Physical Chemistry of Solid Surfaces, The Key Laboratory for Chemical Biology of Fujian Province, and Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiaoyuan Chen
- ‡ Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
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48
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Sebastián N, Osterman N, Lisjak D, Čopič M, Mertelj A. Director reorientation dynamics of ferromagnetic nematic liquid crystals. SOFT MATTER 2018; 14:7180-7189. [PMID: 30141811 DOI: 10.1039/c8sm01377b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Successful realization of ferromagnetic nematic liquid crystals has opened up the possibility to experimentally study a completely new set of fundamental physical phenomena. In this contribution we present a detailed investigation of some aspects of the static response and the complex dynamics of ferromagnetic liquid crystals under the application of an external magnetic field. Experimental results are then compared with a macroscopic model. Dynamics of the director were measured by optical methods and analyzed in terms of a theoretical macroscopic model. A dissipative cross-coupling coefficient describing the dynamic coupling between the two system order parameters, the magnetization and the nematic director, is needed to explain the results. In this contribution we examine the dependency of this coefficient on material parameters and the saturation magnetization and the liquid crystal host. Despite the complexity of the system, the theoretical description allows for a proper interpretation of the results and is connected to several microscopic aspects of the colloidal suspension.
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Affiliation(s)
- Nerea Sebastián
- J. Stefan Institute, P.O.B 3000, SI-1000 Ljubljana, Slovenia.
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49
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Abstract
An effective Landau-like description of ferronematics, i.e., suspensions of magnetic colloidal particles in a nematic liquid crystal (NLC), is developed in terms of the corresponding magnetization and nematic director fields. The study is based on a microscopic model and on classical density functional theory. Ferronematics are susceptible to weak magnetic fields and they can exhibit a ferromagnetic phase, which has been predicted several decades ago and has recently been found experimentally. Within the proposed effective Landau theory of ferronematics, one has quantitative access, e.g., to the coupling between the magnetization of the magnetic colloids and the nematic director of the NLC. On mesoscopic length scales, this generates complex response patterns.
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Affiliation(s)
- Grigorii Zarubin
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, 70569 Stuttgart, Germany and IV. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - Markus Bier
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, 70569 Stuttgart, Germany and IV. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - S Dietrich
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, 70569 Stuttgart, Germany and IV. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
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50
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Makovec D, Belec B, Goršak T, Lisjak D, Komelj M, DraŽić G, Gyergyek S. Discrete evolution of the crystal structure during the growth of Ba-hexaferrite nanoplatelets. NANOSCALE 2018; 10:14480-14491. [PMID: 30022216 DOI: 10.1039/c8nr03815e] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
An understanding of the adaptation of the crystal structure of materials confined at the nanoscale, the influences of their specific structures on the evolution of their morphologies and, finally, their functional properties is essential not only for expanding fundamental knowledge, but also for facilitating the designs of novel nanostructures for diverse technological and medical applications. Here we describe how the distinct structure of barium-hexaferrite nanoplatelets evolves in a stepwise manner in parallel with the development of their size and morphology during hydrothermal synthesis. The nanoplatelets are formed by reactions between Ba- and Fe-hydroxides in an aqueous suspension at temperatures below 80 °C. Scanning-transmission electron microscopy showed that the structure of the as-synthesized, discoid nanoplatelets (∼2.3 nm thick, ∼10 nm wide) terminates at the basal surfaces with Ba-containing planes. However, after subsequent washing of the nanoplatelets with water the top two atomic layers dissolve from the surfaces. The final structure can be represented by a SRS* sequence of the barium-hexaferrite SRS*R* unit cell, where S and R represent a hexagonal (BaFe6O11)2- and a cubic (Fe6O8)2+ structural block, respectively. Due to the stable SRS* structure, the thickness of the primary nanoplatelets remains unchanged up to approximately 150 °C, when some of the primary nanoplatelets start to grow exaggeratedly and their thicknesses increase discretely with the addition of the RS segments to their structure. The SRS* structure of the primary nanoplatelets is too thin for the complete development of magnetic ordering. However, the addition of just one RS segment (SRS*R*S structure) gives the nanoplatelets hard magnetic properties.
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Affiliation(s)
- D Makovec
- Department for Materials Synthesis, JoŽef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia.
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