1
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Jin Y, Perez-Lemus GR, Zubieta Rico PF, de Pablo JJ. Improving Machine Learned Force Fields for Complex Fluids through Enhanced Sampling: A Liquid Crystal Case Study. J Phys Chem A 2024; 128:7257-7268. [PMID: 39150905 DOI: 10.1021/acs.jpca.4c01546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2024]
Abstract
Machine learned force fields offer the potential for faster execution times while retaining the accuracy of traditional DFT calculations, making them promising candidates for molecular simulations in cases where reliable classical force fields are not available. Some of the challenges associated with machine learned force fields include simulation stability over extended periods of time and ensuring that the statistical and dynamical properties of the underlying simulated systems are correctly captured. In this work, we propose a systematic training pipeline for such force fields that leads to improved model quality, compared to that achieved by traditional data generation and training approaches. That pipeline relies on the use of enhanced sampling techniques, and it is demonstrated here in the context of a liquid crystal, which exemplifies many of the challenges that are encountered in fluids and materials with complex free energy landscapes. Our results indicate that, whereas the majority of traditional machine learned force field training approaches lead to molecular dynamics simulations that are only stable over hundred-picosecond trajectories, our approach allows for stable simulations over tens of nanoseconds for organic molecular systems comprising thousands of atoms.
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Affiliation(s)
- Yezhi Jin
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637-1476, United States
| | - Gustavo R Perez-Lemus
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637-1476, United States
| | - Pablo F Zubieta Rico
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637-1476, United States
| | - Juan J de Pablo
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637-1476, United States
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2
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Money J, Munguia-Fernández JG, Norouzi S, Esmaeili M, Martínez-González JA, Sadati M. Photonic features of blue phase liquid crystals under curved confinement. Chem Commun (Camb) 2023; 59:12231-12247. [PMID: 37750291 DOI: 10.1039/d3cc03284a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Blue phase (BP) liquid crystals represent a fascinating state of soft matter that showcases unique optical and electro-optical properties. Existing between chiral nematic and isotropic phases, BPs are characterized by a three-dimensional cubic lattice structure resulting in selective Bragg reflections of light and consequent vivid structural colors. However, the practical realization of these material systems is hampered by their narrow thermal stability and multi-domain crystalline nature. This feature article provides an overview of the efforts devoted to stabilizing these phases and creating monodomain structures. In particular, it delves into the complex relationship between geometrical confinement, induced curvature, and the structural stability and photonic features of BPs. Understanding the interaction of curved confinement and structural stability of BPs proves crucially important for the integration of these materials into flexible and miniaturized devices. By shedding light on these critical aspects, this feature review aims to highlight the significance of understanding the coupling effects of physical and mechanical forces on the structural stability of these systems, which can pave the way for the development of efficient and practical devices based on BP liquid crystals.
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Affiliation(s)
- Jeremy Money
- Department of Chemical Engineering, College of Engineering and Computing, University of South Carolina, Columbia, SC, 29208, USA.
| | - Juan G Munguia-Fernández
- Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Av. Parque Chapultepec 1570, San Luis Potosí 78210, SLP, México
| | - Sepideh Norouzi
- Department of Chemical Engineering, College of Engineering and Computing, University of South Carolina, Columbia, SC, 29208, USA.
| | - Mohsen Esmaeili
- Department of Chemical Engineering, College of Engineering and Computing, University of South Carolina, Columbia, SC, 29208, USA.
| | - José A Martínez-González
- Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Av. Parque Chapultepec 1570, San Luis Potosí 78210, SLP, México
| | - Monirosadat Sadati
- Department of Chemical Engineering, College of Engineering and Computing, University of South Carolina, Columbia, SC, 29208, USA.
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3
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Bagchi K, Emeršič T, Martínez-González JA, de Pablo JJ, Nealey PF. Functional soft materials from blue phase liquid crystals. SCIENCE ADVANCES 2023; 9:eadh9393. [PMID: 37494446 PMCID: PMC10371026 DOI: 10.1126/sciadv.adh9393] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 06/27/2023] [Indexed: 07/28/2023]
Abstract
Blue phase (BP) liquid crystals are chiral fluids wherein millions of molecules self-assemble into cubic lattices that are on the order of hundred nanometers. As the unit cell sizes of BPs are comparable to the wavelength of light, they exhibit selective Bragg reflections in the visible. The exploitation of the photonic properties of BPs for technological applications is made possible through photopolymerization, a process that renders mechanical robustness and thermal stability. We review here the preparation and characterization of stimuli-responsive, polymeric photonic crystals based on BPs. We highlight recent studies that demonstrate the promise that polymerized BP photonic crystals hold for colorimetric sensing and dynamic light control. We review using Landau-de Gennes simulations for predicting the self-assembly of BPs and the potential for using theory to guide experimental design. Finally, opportunities for using BPs to synthesize new soft materials, such as highly structured polymer meshes, are discussed.
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Affiliation(s)
- Kushal Bagchi
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
| | - Tadej Emeršič
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
| | - José A Martínez-González
- Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Av. Parque Chapultepec 1570, San Luis Potosí 78210 SLP, Mexico
| | - Juan J de Pablo
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
- Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Paul F Nealey
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
- Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
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4
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Wang H, Zhou H, He W, Yang Z, Cao H, Wang D, Li Y. Research Progress on Blue-Phase Liquid Crystals for Pattern Replication Applications. MATERIALS (BASEL, SWITZERLAND) 2022; 16:194. [PMID: 36614533 PMCID: PMC9821960 DOI: 10.3390/ma16010194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/20/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Blue-Phase Liquid Crystals (BPLCs) are considered to be excellent 3D photonic crystals and have attracted a great deal of attention due to their great potential for advanced applications in a wide range of fields including self-assembling tunable photonic crystals and fast-response displays. BPLCs exhibit promise in patterned applications due to their sub-millisecond response time, three-dimensional cubic structure, macroscopic optical isotropy and high contrast ratio. The diversity of patterned applications developed based on BPLCs has attracted much attention. This paper focuses on the latest advances in blue-phase (BP) materials, including applications in patterned microscopy, electric field driving, handwriting driving, optical writing and inkjet printing. The paper concludes with future challenges and opportunities for BP materials, providing important insights into the subsequent development of BP.
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Affiliation(s)
| | | | - Wanli He
- Correspondence: ; Tel.: +010-62333759
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5
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Norouzi S, Tavera-Vazquez A, Ramirez-de Arellano J, Kim DS, Lopez-Leon T, de Pablo JJ, Martinez-Gonzalez JA, Sadati M. Elastic Instability of Cubic Blue Phase Nano Crystals in Curved Shells. ACS NANO 2022; 16:15894-15906. [PMID: 36166665 DOI: 10.1021/acsnano.2c02799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Many crystallization processes, including biomineralization and ice-freezing, occur in small and curved volumes, where surface curvature can strain the crystal, leading to unusual configurations and defect formation. The role of curvature on crystallization, however, remains poorly understood. Here, we study the crystallization of blue phase (BP) liquid crystals under curved confinement, which provides insights into the mechanism by which BPs reconfigure their three-dimensional lattice structure to adapt to curvature. BPs are a three-dimensional assembly of high-chirality liquid crystal molecules arranged into body-centered (BPI) or simple cubic (BPII) symmetries. BPs with submicrometer cubic-crystalline lattices exhibit tunable Bragg reflection and submillisecond response time to external stimuli such as an electric field, making them attractive for advanced photonic materials. In this work, we have systematically studied BPs confined in spherical shells with well-defined curvature and boundary conditions. The optical behavior of shells has also been examined at room temperature, where the cholesteric structure forms. In the cholesteric phase, perpendicular anchoring generates focal conic domains on the shell's surface, which transition into stripe patterns as the degree of curvature increases. Our results demonstrate that both higher degrees of curvature and strong spatial confinement destabilize BPI and reconfigure that phase to adopt the structure and optical features of BPII. We also show that the coupling of curvature and confinement nucleates skyrmions at greater thicknesses than those observed for a flat geometry. These findings are particularly important for integrating BPs into miniaturized and curved/flexible devices, including flexible displays, wearable sensors, and smart fabrics.
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Affiliation(s)
- Sepideh Norouzi
- Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Antonio Tavera-Vazquez
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Johanan Ramirez-de Arellano
- Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Avenida Parque Chapultepec 1570, San Luis Potosí 78210, San Luis Potosi México
| | - Dae Seok Kim
- Department of Polymer Engineering, Pukyong National University, Busan 48513, South Korea
| | - Teresa Lopez-Leon
- Laboratoire Gulliver, UMR CNRS 7083, ESPCI Paris, Université PSL, 10 rue Vauquelin, 75005 Paris, France
| | - Juan J de Pablo
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
- Argonne National Laboratory, 9700 Cass Avenue, Lemont, Illinois 60439, United States
| | - Jose A Martinez-Gonzalez
- Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Avenida Parque Chapultepec 1570, San Luis Potosí 78210, San Luis Potosi México
| | - Monirosadat Sadati
- Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States
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6
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Yang Y, Palacio-Betancur V, Wang X, de Pablo JJ, Abbott NL. Strongly Chiral Liquid Crystals in Nanoemulsions. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2105835. [PMID: 35023609 DOI: 10.1002/smll.202105835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 11/22/2021] [Indexed: 06/14/2023]
Abstract
Liquid crystal (LC) emulsions represent a class of confined soft matter that exhibit exotic internal organizations and size-dependent properties, including responses to chemical and physical stimuli. Past studies have explored micrometer-scale LC emulsion droplets but little is known about LC ordering within submicrometer-sized droplets. This paper reports experiments and simulations that unmask the consequences of confinement in nanoemulsions on strongly chiral LCs that form bulk cholesteric and blue phases (BPs). A method based on light scattering is developed to characterize phase transitions of LCs within the nanodroplets. For droplets with a radius to the pitch ratio (Rv /p0 ) as small as 2/3, the BP-to-cholesteric transition is substantially suppressed, leading to a threefold increase of the BP temperature interval relative to bulk behavior. Complementary simulations align with experimental findings and reveal the dominant role of chiral elastic energy. For Rv /p0 ≈ 1/3, a single LC phase forms below the clearing point, with simulations revealing the new configuration to contain a τ-1/2 disclination that extends across the nanodroplet. These findings are discussed in the context of mechanisms by which polymer networks stabilize BPs and, more broadly, for the design of nanoconfined soft matter.
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Affiliation(s)
- Yu Yang
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, 14853, USA
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | | | - Xin Wang
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - Juan J de Pablo
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, 60637, USA
- Center for Molecular Engineering, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Nicholas L Abbott
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, 14853, USA
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7
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Fan B, Wan J, Zhai J, Teo NKS, Huynh A, Thang SH. Photoluminescent polymer cubosomes prepared by RAFT-mediated polymerization-induced self-assembly. Polym Chem 2022. [DOI: 10.1039/d2py00701k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The preparation of photoluminescent polymer assemblies with a wide range of morphologies, including spongosomes and cubosomes, via an efficient RAFT-mediated polymerization-induced self-assembly (RAFT-PISA) process, was demonstrated.
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Affiliation(s)
- Bo Fan
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia
- ARC Centre of Excellence for Enabling Eco-Efficient Beneficiation of Minerals, Monash Node, VIC 3800, Australia
| | - Jing Wan
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia
| | - Jiali Zhai
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | | | - Andy Huynh
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia
| | - San H. Thang
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia
- ARC Centre of Excellence for Enabling Eco-Efficient Beneficiation of Minerals, Monash Node, VIC 3800, Australia
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8
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Sadati M, Martinez-Gonzalez JA, Cohen A, Norouzi S, Guzmán O, de Pablo JJ. Control of Monodomain Polymer-Stabilized Cuboidal Nanocrystals of Chiral Nematics by Confinement. ACS NANO 2021; 15:15972-15981. [PMID: 34597503 DOI: 10.1021/acsnano.1c04231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Liquid crystals are important components of optical technologies. Cuboidal crystals consisting of chiral liquid crystals-the so-called blue phases (BPs), are of particular interest due to their crystalline structures and fast response times, but it is critical that control be gained over their phase behavior as well as the underlying dislocations and grain boundaries that arise in such systems. Blue phases exhibit cubic crystalline symmetries with lattice parameters in the 100 nm range and a network of disclination lines that can be polymerized to widen the range of temperatures over which they occur. Here, we introduce the concept of strain-controlled polymerization of BPs under confinement, which enables formation of strain-correlated stabilized morphologies that, under some circumstances, can adopt perfect single-crystal monodomain structures and undergo reversible crystal-to-crystal transformations, even if their disclination lines are polymerized. We have used super-resolution laser confocal microscopy to reveal the periodic structure and the lattice planes of the strain and polymerization stabilized BPs in 3D real space. Our experimental observations are supported and interpreted by relying on theory and computational simulations in terms of a free energy functional for a tensorial order parameter. Simulations are used to determine the orientation of the lattice planes unambiguously. The findings presented here offer opportunities for engineering optical devices based on single-crystal, polymer-stabilized BPs whose inherent liquid nature, fast dynamics, and long-range crystalline order can be fully exploited.
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Affiliation(s)
- Monirosadat Sadati
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
- Department of Chemical Engineering, Swearingen Engineering Center, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Jose A Martinez-Gonzalez
- Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Av. Parque Chapultepec 1570, San Luis Potosí 78295, SLP, Mexico
| | - Alexander Cohen
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Sepideh Norouzi
- Department of Chemical Engineering, Swearingen Engineering Center, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Orlando Guzmán
- Departamento de Física, Universidad Autonóma Metropolitana, Av. San Rafael Atlixco 186, Ciudad de México 09340, Mexico
| | - Juan J de Pablo
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
- Argonne National Laboratory, 9700 Cass Avenue Lemont, Illinois 60439, United States
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9
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Blue Phase Liquid Crystals with Tailored Crystal Orientation for Photonic Applications. Symmetry (Basel) 2021. [DOI: 10.3390/sym13091584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Blue phase (BP) liquid crystals, which self-assemble into soft three-dimensional (3D) photonic crystals, have attracted enormous research interest due to their ability to control light and potential photonic applications. BPs have long been known as optically isotropic materials, but recent works have revealed that achieving on-demand 3D orientation of BP crystals is necessary to obtain improved electro-optical performance and tailored optical characteristics. Various approaches have been proposed to precisely manipulate the crystal orientation of BPs on a substrate, through the assistance of external stimuli and directing self-assembly processes. Here, we discuss the various orientation-controlling technologies of BP crystals, with their mechanisms, advantages, drawbacks, and promising applications. This review first focuses on technologies to achieve the uniform crystal plane orientation of BPs on a substrate. Further, we review a strategy to control the azimuthal orientation of BPs along predesigned directions with a uniform crystal plane, allowing the 3D orientation to be uniquely defined on a substrate. The potential applications such as volume holograms are also discussed with their operation principle. This review provides significant advances in 3D photonic crystals and gives a huge potential for intelligent photonic devices with tailored optical characteristics.
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10
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Yang Y, Wang L, Yang H, Li Q. 3D Chiral Photonic Nanostructures Based on Blue‐Phase Liquid Crystals. SMALL SCIENCE 2021. [DOI: 10.1002/smsc.202100007] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Yanzhao Yang
- School of Materials Science and Engineering Tianjin University Tianjin 300350 China
| | - Ling Wang
- School of Materials Science and Engineering Tianjin University Tianjin 300350 China
| | - Huai Yang
- Department of Materials Science and Engineering College of Engineering Peking University Beijing 100871 China
| | - Quan Li
- Institute of Advanced Materials and School of Chemistry and Chemical Engineering Southeast University Nanjing 211189 China
- Advanced Materials and Liquid Crystal Institute and Chemical Physics Interdisciplinary Program Kent State University Kent OH 44242 USA
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11
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Chen HQ, Wang XY, Bisoyi HK, Chen LJ, Li Q. Liquid Crystals in Curved Confined Geometries: Microfluidics Bring New Capabilities for Photonic Applications and Beyond. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:3789-3807. [PMID: 33775094 DOI: 10.1021/acs.langmuir.1c00256] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The quest for interesting properties and phenomena in liquid crystals toward their employment in nondisplay application is an intense and vibrant endeavor. Remarkable progress has recently been achieved with regard to liquid crystals in curved confined geometries, typically represented as enclosed spherical geometries and cylindrical geometries with an infinitely extended axial-symmetrical space. Liquid-crystal emulsion droplets and fibers are intriguing examples from these fields and have attracted considerable attention. It is especially noteworthy that the rapid development of microfluidics brings about new capabilities to generate complex soft microstructures composed of both thermotropic and lyotropic liquid crystals. This review attempts to outline the recent developments related to the liquid crystals in curved confined geometries by focusing on microfluidics-mediated approaches. We highlight a wealth of novel photonic applications and beyond and also offer perspectives on the challenges, opportunities, and new directions for future development in this emerging research area.
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Affiliation(s)
- Han-Qing Chen
- Department of Electronic Engineering, School of Electronic Science and Engineering, Xiamen University, Xiamen, Fujian Province 361005, China
| | - Xi-Yuan Wang
- Department of Electronic Engineering, School of Electronic Science and Engineering, Xiamen University, Xiamen, Fujian Province 361005, China
| | - Hari Krishna Bisoyi
- Advanced Materials and Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, United States
| | - Lu-Jian Chen
- Department of Electronic Engineering, School of Electronic Science and Engineering, Xiamen University, Xiamen, Fujian Province 361005, China
| | - Quan Li
- Institute of Advanced Materials and School of Chemistry and Chemical Engineering, Southeast University, Nanjing, Jiangsu Province 211189, China
- Advanced Materials and Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, United States
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12
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Bao P, Paterson DA, Peyman SA, Jones JC, Sandoe JAT, Gleeson HF, Evans SD, Bushby RJ. Production of giant unilamellar vesicles and encapsulation of lyotropic nematic liquid crystals. SOFT MATTER 2021; 17:2234-2241. [PMID: 33469638 DOI: 10.1039/d0sm01684e] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We describe a modified microfluidic method for making Giant Unilamellar Vesicles (GUVs) via water/octanol-lipid/water double emulsion droplets. At a high enough lipid concentration we show that the de-wetting of the octanol from these droplets occurs spontaneously (off-chip) without the need to use shear to aid the de-wetting process. The resultant mixture of octanol droplets and GUVs can be separated by making use of the buoyancy of the octanol. A simpler microfluidic device and pump system can be employed and, because of the higher flow-rates and much higher rate of formation of the double emulsion droplets (∼1500 s-1 compared to up to ∼75 s-1), it is easier to make larger numbers of GUVs and larger volumes of solution. Because of the potential for using GUVs that incorporate lyotropic nematic liquid crystals in biosensors we have used this method to make GUVs that incorporate the nematic phases of sunset yellow and disodium chromoglycate. However, the phase behaviour of these lyotropic liquid crystals is quite sensitive to concentration and we found that there is an unexpected spread in the concentration of the contents of the GUVs obtained.
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Affiliation(s)
- Peng Bao
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Daniel A Paterson
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK and School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK.
| | - Sally A Peyman
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK and Leeds Institute of Medical Research, University of Leeds, Leeds, LS2 9JT, UK
| | - J Cliff Jones
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Jonathan A T Sandoe
- Leeds Institute of Medical Research, University of Leeds, Leeds, LS2 9JT, UK
| | - Helen F Gleeson
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Stephen D Evans
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
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13
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Pilkington CP, Seddon JM, Elani Y. Microfluidic technologies for the synthesis and manipulation of biomimetic membranous nano-assemblies. Phys Chem Chem Phys 2021; 23:3693-3706. [PMID: 33533338 DOI: 10.1039/d0cp06226j] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Microfluidics has been proposed as an attractive alternative to conventional bulk methods used in the generation of self-assembled biomimetic structures, particularly where there is a desire for more scalable production. The approach also allows for greater control over the self-assembly process, and parameters such as particle architecture, size, and composition can be finely tuned. Microfluidic techniques used in the generation of microscale assemblies (giant vesicles and higher-order multi-compartment assemblies) are fairly well established. These tend to rely on microdroplet templation, and the resulting structures have found use as comparmentalised motifs in artificial cells. Challenges in generating sub-micron droplets have meant that reconfiguring this approach to form nano-scale structures is not straightforward. This is beginning to change however, and recent technological advances have instigated the manufacture and manipulation of an increasingly diverse repertoire of biomimetic nano-assemblies, including liposomes, polymersomes, hybrid particles, multi-lamellar structures, cubosomes, hexosomes, nanodiscs, and virus-like particles. The following review will discuss these higher-order self-assembled nanostructures, including their biochemical and industrial applications, and techniques used in their production and analysis. We suggest ways in which existing technologies could be repurposed for the enhanced design, manufacture, and exploitation of these structures and discuss potential challenges and future research directions. By compiling recent advances in this area, it is hoped we will inspire future efforts toward establishing scalable microfluidic platforms for the generation of biomimetic nanoparticles of enhanced architectural and functional complexity.
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Affiliation(s)
- Colin P Pilkington
- Department of Chemistry, Molecular Science Research Hub, Imperial College London, 82 Wood Lane, London, W12 0BZ, UK and Department of Chemical Engineering, Exhibition Road, Imperial College London, London, SW7 2AZ, UK.
| | - John M Seddon
- Department of Chemistry, Molecular Science Research Hub, Imperial College London, 82 Wood Lane, London, W12 0BZ, UK
| | - Yuval Elani
- Department of Chemical Engineering, Exhibition Road, Imperial College London, London, SW7 2AZ, UK.
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14
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Wang L, Urbas AM, Li Q. Nature-Inspired Emerging Chiral Liquid Crystal Nanostructures: From Molecular Self-Assembly to DNA Mesophase and Nanocolloids. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1801335. [PMID: 30160812 DOI: 10.1002/adma.201801335] [Citation(s) in RCA: 162] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/17/2018] [Indexed: 05/22/2023]
Abstract
Liquid crystals (LCs) are omnipresent in living matter, whose chirality is an elegant and distinct feature in certain plant tissues, the cuticles of crabs, beetles, arthropods, and beyond. Taking inspiration from nature, researchers have recently devoted extensive efforts toward developing chiral liquid crystalline materials with self-organized nanostructures and exploring their potential applications in diverse fields ranging from dynamic photonics to energy and safety issues. In this review, an account on the state of the art of emerging chiral liquid crystalline nanostructured materials and their technological applications is provided. First, an overview on the significance of chiral liquid crystalline architectures in various living systems is given. Then, the recent significant progress in different chiral liquid crystalline systems including thermotropic LCs (cholesteric LCs, cubic blue phases, achiral bent-core LCs, etc.) and lyotropic LCs (DNA LCs, nanocellulose LCs, and graphene oxide LCs) is showcased. The review concludes with a perspective on the future scope, opportunities, and challenges in these truly advanced functional soft materials and their promising applications.
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Affiliation(s)
- Ling Wang
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH, 44242, USA
| | - Augustine M Urbas
- Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, OH, 45433, USA
| | - Quan Li
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH, 44242, USA
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15
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Yang Y, Kim YK, Wang X, Tsuei M, Abbott NL. Structural and Optical Response of Polymer-Stabilized Blue Phase Liquid Crystal Films to Volatile Organic Compounds. ACS APPLIED MATERIALS & INTERFACES 2020; 12:42099-42108. [PMID: 32794738 DOI: 10.1021/acsami.0c11138] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Engineering useful mechanical properties into stimuli-responsive soft materials without compromising their responsiveness is, in many cases, an unresolved challenge. For example, polymer networks formed within blue-phase liquid crystals (BPs) have been shown to form mechanically robust films, but the impact of polymer networks on the response of these soft materials to chemical stimuli has not been explored. Here, we report on the response of polymer-stabilized BPs (PSBPs) to volatile organic compounds (VOCs, using toluene as a model compound) and compare the response to BPs without polymer stabilization and to polymerized nematic and cholesteric phases. We find that PSBPs generate an optical response to toluene vapor (change in reflection intensity under crossed polars) that is sixfold greater in sensitivity than the polymerized nematic or cholesteric phases and with a limit of detection (140 ± 10 ppm at 25 °C) that is relevant to the measurement of permissible exposure limits for humans. Additionally, when compared to BPs that have not been polymerized, PSBPs respond to a broader range of toluene vapor concentrations (5000 vs <1000 ppm) over a wider temperature interval (25-45 vs 45-53 °C). We place these experimental observations into the context of a simple thermodynamic model to explore how the PSBP response reflects the effect of toluene on competing contributions of double-twisted LC cylinders, disclinations, and polymer network to the free energy that controls the PSBP lattice spacing. Overall, we conclude that the mechanical and thermal stability of PSBPs, when combined with their optical responsiveness to toluene, make this class of self-supporting LCs a promising one as the basis of passive and compact (e.g., wearable) sensors for VOCs.
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Affiliation(s)
- Yu Yang
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Young-Ki Kim
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Xin Wang
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Michael Tsuei
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Nicholas L Abbott
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
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16
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Sadati M, Martinez-Gonzalez JA, Zhou Y, Qazvini NT, Kurtenbach K, Li X, Bukusoglu E, Zhang R, Abbott NL, Hernandez-Ortiz JP, de Pablo JJ. Prolate and oblate chiral liquid crystal spheroids. SCIENCE ADVANCES 2020; 6:eaba6728. [PMID: 32832603 PMCID: PMC7439570 DOI: 10.1126/sciadv.aba6728] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 05/28/2020] [Indexed: 05/15/2023]
Abstract
Liquid crystals are known to exhibit intriguing textures and color patterns, with applications in display and optical technologies. This work focuses on chiral materials and examines the palette of morphologies that arises when microdroplets are deformed into nonspherical shapes in a controllable manner. Specifically, geometrical confinement and mechanical strain are used to manipulate orientational order, phase transitions, and topological defects that arise in chiral liquid crystal droplets. Inspired by processes encountered in nature, where insects and animals often rely on strain and temperature to alter the optical appearance of dispersed liquid crystalline elements, chiral droplets are dispersed in polymer films and deformation induced by uniaxial or biaxial stretching. Our measurements are interpreted by resorting to simulations of the corresponding systems, thereby providing an in-depth understanding of the morphologies that arise in these materials. The reported structures and assemblies offer potential for applications in smart coatings, smart fabrics, and wearable sensors.
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Affiliation(s)
- Monirosadat Sadati
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Department of Chemical Engineering, Swearingen Engineering Center, University of South Carolina, Columbia, SC 29208, USA
| | - Jose A. Martinez-Gonzalez
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Av. Parque Chapultepec 1570, San Luis Potosí 78295, SLP, México
| | - Ye Zhou
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Nader Taheri Qazvini
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Department of Chemical Engineering, Swearingen Engineering Center, University of South Carolina, Columbia, SC 29208, USA
| | - Khia Kurtenbach
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Xiao Li
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Department of Materials Science and Engineering, University of North Texas, Denton, TX 76203, USA
| | - Emre Bukusoglu
- Chemical Engineering Department, Middle East Technical University, Ankara 06800, Turkey
| | - Rui Zhang
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Nicholas L. Abbott
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Juan Pablo Hernandez-Ortiz
- Departamento de Materiales y Minerales, Facultad de Minas, Universidad Nacional de Colombia, Sede Medellín, Calle 75 # 79A-51, Bloque M17, Medellín, Colombia
| | - Juan J. de Pablo
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Argonne National Laboratory, 9700 Cass Avenue, Lemont, IL 60439, USA
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17
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Orzechowski K, Sala-Tefelska MM, Sierakowski MW, Woliński TR, Strzeżysz O, Kula P. Optical properties of cubic blue phase liquid crystal in photonic microstructures. OPTICS EXPRESS 2019; 27:14270-14282. [PMID: 31163878 DOI: 10.1364/oe.27.014270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 04/11/2019] [Indexed: 06/09/2023]
Abstract
In this work, optical properties of a cubic blue phase liquid crystal (BPLC) in photonic microstructures were investigated. The experiments were carried out in microcapillaries with different inner diameters and in a photonic crystal fiber (PCF). For the first time, white-light beam propagation through a BPLC (BP II) in a microcapillary with a 60-μm inner diameter at a distance of 26 mm was demonstrated. Furthermore, it was conclusively shown that the cylindrical geometry and the size of its inner diameter influence BP domains orientation, which can lead to a uniform texture of the BPLC with a dominant Bragg wavelength. This study also proves that a BPLC-filled PCF provides very attractive tunable properties. It was presented that by applying an external electric field, a control of the transmitted light intensity for particular wavelengths can be achieved, depending on the input polarization. Moreover, a range of the wavelengths corresponding to low transmission appeared to be tunable, whereas for x- and y-polarized light, respectively, both narrowing (from 16 nm to 9 nm) as well widening (from 13 nm to 22 nm) of the bandgaps were observed. Finally, the obtained experimental results were found qualitatively consistent.
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18
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Wang X, Zhou Y, Kim YK, Tsuei M, Yang Y, de Pablo JJ, Abbott NL. Thermally reconfigurable Janus droplets with nematic liquid crystalline and isotropic perfluorocarbon oil compartments. SOFT MATTER 2019; 15:2580-2590. [PMID: 30816895 DOI: 10.1039/c8sm02600a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report that mixtures of perfluorocarbon oils and hydrocarbon mesogens can be used to prepare multi-compartment (Janus) emulsion drops comprising coexisting nematic liquid crystalline (LC) and isotropic oil phases. The droplets exhibit stable spherical shapes with internal Janus-type morphologies that can be tuned widely through changes in temperature or adsorbates. In particular, we observe evidence of preferential adsorption of hydrocarbon or fluorocarbon surfactants on the interfaces of nematic versus isotropic domains, respectively, providing added control over the droplet structure. Comparisons of experiments and numerical simulations using a Landau-de Gennes continuum model provide insight into the relative importance of the LC elasticity and orientational-dependent interfacial energies on droplet morphologies and properties. We show that the hierarchical organization of the LC compartments generates optical properties and responsiveness not found in emulsions of isotropic oils.
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Affiliation(s)
- Xin Wang
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA.
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19
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Li X, Martínez-González JA, Park K, Yu C, Zhou Y, de Pablo JJ, Nealey PF. Perfection in Nucleation and Growth of Blue-Phase Single Crystals: Small Free-Energy Required to Self-Assemble at Specific Lattice Orientation. ACS APPLIED MATERIALS & INTERFACES 2019; 11:9487-9495. [PMID: 30763069 DOI: 10.1021/acsami.8b18078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Chemically patterned surfaces can be used to selectively stabilize blue phases as macroscopic single crystals with a prescribed lattice orientation. By tailoring the interfacial free energy through the pattern characteristics, it is possible to set, with nanoscale precision, the optimal conditions to induce spontaneously blue-phase crystal nucleation on the patterned substrate where a uniform, defect-free, blue-phase single crystal is finally formed in a matter of seconds. The chemical patterns taken into consideration in this work are made up of alternated stripelike regions of homeotropic and planar anchoring. By varying the stripe pattern dimension, including the period and ratio of the planar/homeotropic anchoring width, it is possible to generate blue-phase I single crystals with (110) lattice orientation and blue-phase II single crystals with either the (100), (110), or (111) lattice orientation. Continuum mean-field calculations of the studied systems serve to explain, in terms of the free energy of the systems, how the pattern dimensions favor certain crystallographic orientations while penalizing the others. We found that a small free-energy difference is sufficient to drive the nucleation and growth of blue phases into a certain lattice orientation. Therefore, a processing window for obtaining arbitrary large blue-phase single crystals with predesigned lattice orientation, highly aligned reflective peaks, and significantly short forming time is provided here, which is essential for manufacturing and modulating optical devices and photonics.
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Affiliation(s)
- Xiao Li
- Institute for Molecular Engineering , The University of Chicago , Chicago , Illinois 60637 , United States
- Material Science Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Jose A Martínez-González
- Facultad de Ciencias , Universidad Autónoma de San Luis Potosí , Av. Parque Chapultepec 1570 s/n , San Luis Potosí 78295 , Mexico
| | - Kangho Park
- Institute for Molecular Engineering , The University of Chicago , Chicago , Illinois 60637 , United States
- Department of Chemical and Biomolecular Engineering , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , South Korea
| | - Cecilia Yu
- Institute for Molecular Engineering , The University of Chicago , Chicago , Illinois 60637 , United States
| | - Ye Zhou
- Institute for Molecular Engineering , The University of Chicago , Chicago , Illinois 60637 , United States
| | - Juan J de Pablo
- Institute for Molecular Engineering , The University of Chicago , Chicago , Illinois 60637 , United States
- Material Science Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Paul F Nealey
- Institute for Molecular Engineering , The University of Chicago , Chicago , Illinois 60637 , United States
- Material Science Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
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20
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Srinivasarao DA, Lohiya G, Katti DS. Fundamentals, challenges, and nanomedicine‐based solutions for ocular diseases. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2018; 11:e1548. [DOI: 10.1002/wnan.1548] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 09/21/2018] [Accepted: 10/28/2018] [Indexed: 01/07/2023]
Affiliation(s)
- Dadi A. Srinivasarao
- Department of Biological Sciences and Bioengineering Indian Institute of Technology Kanpur Kanpur India
| | - Garima Lohiya
- Department of Biological Sciences and Bioengineering Indian Institute of Technology Kanpur Kanpur India
| | - Dhirendra S. Katti
- Department of Biological Sciences and Bioengineering Indian Institute of Technology Kanpur Kanpur India
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21
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Kim SU, Lee SH, Lee IH, Lee BY, Na JH, Lee SD. Generation of intensity-tunable structural color from helical photonic crystals for full color reflective-type display. OPTICS EXPRESS 2018; 26:13561-13572. [PMID: 29801380 DOI: 10.1364/oe.26.013561] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 05/08/2018] [Indexed: 06/08/2023]
Abstract
A new concept of intensity-tunable structural coloration is proposed on the basis of a helical photonic crystal (HPC). The HPCs are constructed from a mixture of chiral reactive mesogens by spin-coating, followed by the photo-polymerization. A liquid crystal (LC) layer, being homogeneously aligned, is prepared on the HPCs to serve as a tunable waveplate. The electrical modulation of the phase retardation through the LC layer directly leads to the intensity-tunable Bragg reflection from the HPCs upon the incidence of the polarized light. The bandwidths of the structural colors are found to be well preserved regardless of the applied voltage. A prototype of a full color reflective-type display, incorporated with three primary color units, is demonstrated. Our concept of decoupling two mutually independent functions, the intensity modulation by the tunable waveplate and the color reflection by the HPCs provides a simple and powerful way of producing a full color reflective-type display which possesses high color purity, high optical efficiency, the cycling durability, and the design flexibility.
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22
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Wang L, Li Q. Photochromism into nanosystems: towards lighting up the future nanoworld. Chem Soc Rev 2018; 47:1044-1097. [PMID: 29251304 DOI: 10.1039/c7cs00630f] [Citation(s) in RCA: 334] [Impact Index Per Article: 55.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ability to manipulate the structure and function of promising nanosystems via energy input and external stimuli is emerging as an attractive paradigm for developing reconfigurable and programmable nanomaterials and multifunctional devices. Light stimulus manifestly represents a preferred external physical and chemical tool for in situ remote command of the functional attributes of nanomaterials and nanosystems due to its unique advantages of high spatial and temporal resolution and digital controllability. Photochromic moieties are known to undergo reversible photochemical transformations between different states with distinct properties, which have been extensively introduced into various functional nanosystems such as nanomachines, nanoparticles, nanoelectronics, supramolecular nanoassemblies, and biological nanosystems. The integration of photochromism into these nanosystems has endowed the resultant nanostructures or advanced materials with intriguing photoresponsive behaviors and more sophisticated functions. In this Review, we provide an account of the recent advancements in reversible photocontrol of the structures and functions of photochromic nanosystems and their applications. The important design concepts of such truly advanced materials are discussed, their fabrication methods are emphasized, and their applications are highlighted. The Review is concluded by briefly outlining the challenges that need to be addressed and the opportunities that can be tapped into. We hope that the review of the flourishing and vibrant topic with myriad possibilities would shine light on exploring the future nanoworld by encouraging and opening the windows to meaningful multidisciplinary cooperation of engineers from different backgrounds and scientists from the fields such as chemistry, physics, engineering, biology, nanotechnology and materials science.
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Affiliation(s)
- Ling Wang
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, USA.
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23
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Bukusoglu E, Martinez-Gonzalez JA, Wang X, Zhou Y, de Pablo JJ, Abbott NL. Strain-induced alignment and phase behavior of blue phase liquid crystals confined to thin films. SOFT MATTER 2017; 13:8999-9006. [PMID: 29164213 DOI: 10.1039/c7sm01755c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report on the influence of surface confinement on the phase behavior and strain-induced alignment of thin films of blue phase liquid crystals (BPs). Confining surfaces comprised of bare glass, dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride (DMOAP)-functionalized glass, or polyvinyl alcohol (PVA)-coated glass were used with or without mechanically rubbing to influence the azimuthal anchoring of the BPs. These experiments reveal that confinement can change the phase behavior of the BP films. For example, in experiments performed with rubbed-PVA surfaces, we measured the elastic strain of the BPs to change the isotropic-BPII phase boundary, suppressing formation of BPII for film thicknesses incommensurate with the BPII lattice. In addition, we observed strain-induced alignment of the BPs to exhibit a complex dependence on both the surface chemistry and azimuthal alignment of the BPs. For example, when using bare glass surfaces causing azimuthally degenerate and planar anchoring, BPI oriented with (110) planes of the unit cell parallel to the contacting surfaces for thicknesses below 3 μm but transitioned to an orientation with (200) planes aligned parallel to the contacting surfaces for thicknesses above 4 μm. In contrast, BPI aligned with (110) planes parallel to confining surfaces for all other thicknesses and surface treatments, including bare glass with uniform azimuthal alignment. Complementary simulations based on minimization of the total free energy (Landau-de Gennes formalism) confirmed a thickness-dependent reorientation due to strain of BPI unit cells within a window of surface anchoring energies and in the absence of uniform azimuthal alignment. In contrast to BPI, BPII did not exhibit thickness-dependent orientations but did exhibit orientations that were dependent on the surface chemistry, a result that was also captured in simulations by varying the anchoring energies. Overall, the results in this paper reveal that the orientations assumed by BPs in thin films reflect a complex interplay of surface interactions and elastic energies associated with strain of the BP lattice. The results also provide new principles and methods to control the structure and properties of BP thin films, which may find use in BP-templated material synthesis, and BP-based optical and electronic devices.
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Affiliation(s)
- Emre Bukusoglu
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA.
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24
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Mesoscale martensitic transformation in single crystals of topological defects. Proc Natl Acad Sci U S A 2017; 114:10011-10016. [PMID: 28874557 DOI: 10.1073/pnas.1711207114] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Liquid-crystal blue phases (BPs) are highly ordered at two levels. Molecules exhibit orientational order at nanometer length scales, while chirality leads to ordered arrays of double-twisted cylinders over micrometer scales. Past studies of polycrystalline BPs were challenged by the existence of grain boundaries between randomly oriented crystalline nanodomains. Here, the nucleation of BPs is controlled with precision by relying on chemically nanopatterned surfaces, leading to macroscopic single-crystal BP specimens where the dynamics of mesocrystal formation can be directly observed. Theory and experiments show that transitions between two BPs having a different network structure proceed through local reorganization of the crystalline array, without diffusion of the double-twisted cylinders. In solid crystals, martensitic transformations between crystal structures involve the concerted motion of a few atoms, without diffusion. The transformation between BPs, where crystal features arise in the submicron regime, is found to be martensitic in nature when one considers the collective behavior of the double-twist cylinders. Single-crystal BPs are shown to offer fertile grounds for the study of directed crystal nucleation and the controlled growth of soft matter.
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25
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Wang X, Zhou Y, Kim YK, Miller DS, Zhang R, Martinez-Gonzalez JA, Bukusoglu E, Zhang B, Brown TM, de Pablo JJ, Abbott NL. Patterned surface anchoring of nematic droplets at miscible liquid-liquid interfaces. SOFT MATTER 2017; 13:5714-5723. [PMID: 28752888 DOI: 10.1039/c7sm00975e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report on the internal configurations of droplets of nematic liquid crystals (LCs; 10-50 μm-in-diameter; comprised of 4-cyano-4'-pentylbiphenyl and 4-(3-acryloyloxypropyloxy)benzoic acid 2-methyl-1,4-phenylene ester) sedimented from aqueous solutions of sodium dodecyl sulfate (SDS) onto interfaces formed with pure glycerol. We observed a family of internal LC droplet configurations and topological defects consistent with a remarkably abrupt transition from homeotropic (perpendicular) to tangential anchoring on the surface of the LC droplets in the interfacial environment. Calculations of the interdiffusion of water and glycerol at the aqueous-glycerol interface revealed the thickness of the diffuse interfacial region of the two miscible liquids to be small (0.2-0.5 μm) compared to the diameters of the LC droplets on the experimental time-scale (15-120 minutes), leading us to hypothesize that the patterned surface anchoring was induced by gradients in concentration of SDS and glycerol across the diameter of the LC droplets in the interfacial region. This hypothesis received additional support from experiments in which the time of sedimentation of the LC droplets onto the interface was systematically increased and the droplets were photo-polymerized to preserve their configurations: the configurations of the LC droplets were consistent with a time-dependent decrease in the fraction of the surface area of each droplet exhibiting homeotropic anchoring. Specifically, LC droplets with <10% surface area with tangential anchoring exhibited a bulk point defect within the LC droplet, whereas droplets with >10% surface area with tangential anchoring exhibited a boojum defect within the tangential region and a disclination loop separated the regions with tangential and homeotropic anchoring. The topological charge of these LC droplet configurations was found to be consistent with the geometrical theorems of Poincaré and Gauss and also well-described by computer simulations performed by minimization of a Landau-de Gennes free energy. Additional experimental observations (e.g., formation of "Janus-like" particles with one hemisphere exhibiting tangential anchoring and the other perpendicular anchoring) and simulations (e.g., a size-dependent set of LC droplet configurations with <10% surface area exhibiting tangential anchoring) support our general conclusion that placement of LC droplets into miscible liquid-liquid interfacial environments with compositional gradients can lead to a rich set of LC droplet configurations with symmetries and optical characteristics that are not encountered in LC droplet systems in homogeneous, bulk environments. Our results also reveal that translocation of LC droplets across liquid-liquid interfaces can define new transition pathways that connect distinct configurations of LC droplets.
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Affiliation(s)
- Xiaoguang Wang
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
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26
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Martínez-González JA, Li X, Sadati M, Zhou Y, Zhang R, Nealey PF, de Pablo JJ. Directed self-assembly of liquid crystalline blue-phases into ideal single-crystals. Nat Commun 2017. [PMID: 28621314 PMCID: PMC5481765 DOI: 10.1038/ncomms15854] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Chiral nematic liquid crystals are known to form blue phases—liquid states of matter that exhibit ordered cubic arrangements of topological defects. Blue-phase specimens, however, are generally polycrystalline, consisting of randomly oriented domains that limit their performance in applications. A strategy that relies on nano-patterned substrates is presented here for preparation of stable, macroscopic single-crystal blue-phase materials. Different template designs are conceived to exert control over different planes of the blue-phase lattice orientation with respect to the underlying substrate. Experiments are then used to demonstrate that it is indeed possible to create stable single-crystal blue-phase domains with the desired orientation over large regions. These results provide a potential avenue to fully exploit the electro-optical properties of blue phases, which have been hindered by the existence of grain boundaries. Blue phases are a liquid crystalline state with attractive optical properties but their use in devices can be hindered by their polycrystalline nature. Here the authors create monocrystalline blue phase domains by designing substrates with patterns which are determined by field-theoretic simulations.
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Affiliation(s)
- Jose A Martínez-González
- Institute for Molecular Engineering, The University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA.,Material Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Xiao Li
- Institute for Molecular Engineering, The University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA
| | - Monirosadat Sadati
- Institute for Molecular Engineering, The University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA
| | - Ye Zhou
- Institute for Molecular Engineering, The University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA
| | - Rui Zhang
- Institute for Molecular Engineering, The University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA
| | - Paul F Nealey
- Institute for Molecular Engineering, The University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA.,Material Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Juan J de Pablo
- Institute for Molecular Engineering, The University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA.,Material Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
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27
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Kemiklioglu E, Chien LC. Effects of photoinitiator on electro-optical properties of polymerization-induced phase separation blue-phase liquid crystals. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2017; 40:37. [PMID: 28361253 DOI: 10.1140/epje/i2017-11524-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/02/2017] [Indexed: 06/07/2023]
Abstract
We have reported polymer-dispersed blue-phase (PDBP) liquid-crystal films via polymerization-induced phase separation. PDBP films are prepared by photochemical polymerization of curable crosslinking agent, monomer and blue-phase liquid crystal under an ultraviolet (UV) light. The influences of photoinitiator and weight ratio between monomer/crosslinking agent and blue phase on the electro-optical properties of PDBP liquid-crystal samples are investigated. The electro-optical (E-O) properties of PDBP films are determined in the top-down electro-optical cell. PDBP liquid-crystal films show good E-O properties with high contrast ratio and fast response time.
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Affiliation(s)
- Emine Kemiklioglu
- Engineering Faculty, Manisa Celal Bayar University, Manisa, Muradiye, Turkey.
| | - Liang-Chy Chien
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH, USA
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28
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Sadati M, Ramezani-Dakhel H, Bu W, Sevgen E, Liang Z, Erol C, Rahimi M, Taheri Qazvini N, Lin B, Abbott NL, Roux B, Schlossman ML, de Pablo JJ. Molecular Structure of Canonical Liquid Crystal Interfaces. J Am Chem Soc 2017; 139:3841-3850. [PMID: 28177227 DOI: 10.1021/jacs.7b00167] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Numerous applications of liquid crystals rely on control of molecular orientation at an interface. However, little is known about the precise molecular structure of such interfaces. In this work, synchrotron X-ray reflectivity measurements, accompanied by large-scale atomistic molecular dynamics simulations, are used for the first time to reconstruct the air-liquid crystal interface of a nematic material, namely, 4-pentyl-4'-cyanobiphenyl (5CB). The results are compared to those for 4-octyl-4'-cyanobiphenyl (8CB) which, in addition to adopting isotropic and nematic states, can also form a smectic phase. Our findings indicate that the air interface imprints a highly ordered structure into the material; such a local structure then propagates well into the bulk of the liquid crystal, particularly for nematic and smectic phases.
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Affiliation(s)
| | | | | | | | - Zhu Liang
- Department
of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Cem Erol
- Department
of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | | | | | | | - Nicholas L. Abbott
- Department
of Chemical and Biological Engineering, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | | | - Mark L. Schlossman
- Department
of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Juan J. de Pablo
- Argonne National Laboratory, Argonne, Illinois 60439, United States
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29
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Zhou Y, Guo A, Zhang R, Armas-Perez JC, Martínez-González JA, Rahimi M, Sadati M, de Pablo JJ. Mesoscale structure of chiral nematic shells. SOFT MATTER 2016; 12:8983-8989. [PMID: 27722420 DOI: 10.1039/c6sm01284a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
There is considerable interest in understanding and controlling topological defects in nematic liquid crystals (LCs). Confinement, in the form of droplets, has been particularly effective in that regard. Here, we employ a Landau-de Gennes formalism to explore the geometrical frustration of nematic order in shell geometries, and focus on chiral materials. By varying the chirality and thickness in uniform shells, we construct a phase diagram that includes tetravalent structures, bipolar structures (BS), bent structures and radial spherical structures (RSS). It is found that, in uniform shells, the BS-to-RSS structural transition, in response to both chirality and shell geometry, is accompanied by an abrupt change of defect positions, implying a potential use for chiral nematic shells as sensors. Moreover, we investigate thickness heterogeneity in shells and demonstrate that non-chiral and chiral nematic shells exhibit distinct equilibrium positions of their inner core that are governed by shell chirality c.
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Affiliation(s)
- Ye Zhou
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA.
| | - Ashley Guo
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA.
| | - Rui Zhang
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA.
| | - Julio C Armas-Perez
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA.
| | | | - Mohammad Rahimi
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA.
| | - Monirosadat Sadati
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA.
| | - Juan J de Pablo
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA.
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30
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Bukusoglu E, Wang X, Zhou Y, Martínez-González JA, Rahimi M, Wang Q, de Pablo JJ, Abbott NL. Positioning colloids at the surfaces of cholesteric liquid crystal droplets. SOFT MATTER 2016; 12:8781-8789. [PMID: 27722427 DOI: 10.1039/c6sm01661h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report on the internal configurations of aqueous dispersions of droplets of cholesteric liquid crystals (LCs; 5-50 μm-in-diameter; comprised of 4-cyano-4'-pentylbiphenyl and 4-(1-methylheptyloxycarbonyl)phenyl-4-hexyloxybenzoate) and their influence on the positioning of surface-adsorbed colloids (0.2 or 1 μm-in-diameter polystyrene (PS)). When N = 2D/P was less than 4, where D is the droplet diameter and P is the cholesteric pitch, the droplets adopted a twisted bipolar structure (TBS) and colloids were observed to assume positions at either the poles or equator of the droplets. A statistical analysis of the distribution of locations of the colloids revealed a potential well of depth 2.7 kBT near the equator, a conclusion that was supported by computer simulations performed via the minimization of the Landau-de Gennes free energy (well depth of 7 kBT from simulation). In contrast, for N > 4, a majority of the droplets exhibited a radial spherical structure (RSS) characterized by a pair of closely spaced surface defects (angle of separation with respect to the center of the droplet θ < 5°) connected by a disclination winding to/from the droplet center, which led to the positioning of pairs of colloids with well-defined spacing at these surface defects. The separation of the pairs of surface-adsorbed colloids was colloid size-dependent, ranging from 1.11 ± 0.04 μm for 1 μm-in-diameter colloids to 1.7 ± 0.2 μm for 200 nm-in-diameter colloids. We also observed long-lived metastable configurations in which the two surface point defects were separated by much larger distances (corresponding to populations with angles of θ = 20 ± 10° and 85 ± 10° with respect to the center), and observed these pairs of defects to also position pairs of colloids. A third configuration, the diametrical spherical structure (DSS) was also observed. Consistent with the predictions of computer simulations, we found experimentally that the DSS is indeed composed of disconnected defect rings positioned along the diameter of the droplet. Overall, these results reveal that the rich palette of defects exhibited by confined cholesteric LC systems (equilibrium and metastable) provide the basis of a versatile class of templates that enable the surface positioning of colloids in ways that are not possible with achiral LC droplets.
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Affiliation(s)
- Emre Bukusoglu
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
| | - Xiaoguang Wang
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
| | - Ye Zhou
- Institute for Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
| | | | - Mohammad Rahimi
- Institute for Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
| | - Qi Wang
- Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Juan J de Pablo
- Institute for Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
| | - Nicholas L Abbott
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
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31
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Zhou Y, Bukusoglu E, Martínez-González JA, Rahimi M, Roberts TF, Zhang R, Wang X, Abbott NL, de Pablo JJ. Structural Transitions in Cholesteric Liquid Crystal Droplets. ACS NANO 2016; 10:6484-6490. [PMID: 27249186 DOI: 10.1021/acsnano.6b01088] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Confinement of cholesteric liquid crystals (ChLC) into droplets leads to a delicate interplay between elasticity, chirality, and surface energy. In this work, we rely on a combination of theory and experiments to understand the rich morphological behavior that arises from that balance. More specifically, a systematic study of micrometer-sized ChLC droplets is presented as a function of chirality and surface energy (or anchoring). With increasing chirality, a continuous transition is observed from a twisted bipolar structure to a radial spherical structure, all within a narrow range of chirality. During such a transition, a bent structure is predicted by simulations and confirmed by experimental observations. Simulations are also able to capture the dynamics of the quenching process observed in experiments. Consistent with published work, it is found that nanoparticles are attracted to defect regions on the surface of the droplets. For weak anchoring conditions at the nanoparticle surface, ChLC droplets adopt a morphology similar to that of the equilibrium helical phase observed for ChLCs in the bulk. As the anchoring strength increases, a planar bipolar structure arises, followed by a morphological transition to a bent structure. The influence of chirality and surface interactions are discussed in the context of the potential use of ChLC droplets as stimuli-responsive materials for reporting molecular adsorbates.
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Affiliation(s)
- Ye Zhou
- Institute for Molecular Engineering, The University of Chicago , Chicago, Illinois 60637, United States
| | - Emre Bukusoglu
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - José A Martínez-González
- Institute for Molecular Engineering, The University of Chicago , Chicago, Illinois 60637, United States
| | - Mohammad Rahimi
- Institute for Molecular Engineering, The University of Chicago , Chicago, Illinois 60637, United States
| | - Tyler F Roberts
- Institute for Molecular Engineering, The University of Chicago , Chicago, Illinois 60637, United States
| | - Rui Zhang
- Institute for Molecular Engineering, The University of Chicago , Chicago, Illinois 60637, United States
| | - Xiaoguang Wang
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Nicholas L Abbott
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Juan J de Pablo
- Institute for Molecular Engineering, The University of Chicago , Chicago, Illinois 60637, United States
- Argonne National Laboratory , Argonne, Illinois 60439, United States
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