1
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Ma Y, Dicce A, Reddy NR, Fang J. Liquid-crystalline ordering of davydov-split aggregates of cyanine dyes. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128713] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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2
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Yu G, Walker M, Wilson MR. Atomistic simulation studies of ionic cyanine dyes: self-assembly and aggregate formation in aqueous solution. Phys Chem Chem Phys 2021; 23:6408-6421. [PMID: 33705506 DOI: 10.1039/d0cp06205g] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cyanine dyes are known to form large-scale aggregates of various morphologies via spontaneous self-assembly in aqueous solution, akin to chromonic liquid crystals. Atomistic molecular dynamics simulations have been performed on four cyanine dyes: pseudoisocyanine chloride (PIC), pinacyanol chloride (PCYN), 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine chloride (TTBC) and 1,1'-disulfopropyl-3,3'-diethyl-5,5',6,6'-tetrachloro-benzimidazolylcarbocyanine sodium salt (BIC). Simulations employed an optimised general AMBER force field and demonstrate the organisation of the dyes into stacked structures at dilute concentrations. The thermodynamics of self-assembly was studied by calculating potentials of mean force for n-mers (n = 2, 3 or 4), from which the free energies of association are determined. We report binding free energies in the range of 8 to 15kBT for dimerisation, concordant with typical values for ionic chromonics (7 to 14kBT), and examine the enthalpic and entropic contributions to the aggregation process. The self-assembly of these dyes yields two distinct classes of structures. We observe the formation of H-aggregate stacks for PCYN, with further complexity in these assemblies for PIC; where the aggregates contain shift and Y junction defects. TTBC and BIC associate into a J-aggregate sheet structure of unimolecular thickness, and is composed of a brickwork arrangement between molecules. These sheet structures are characteristic of the smectic chromonic mesophase, and such assemblies provide a route to the emergence of nanoscale tubular architectures.
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Affiliation(s)
- Gary Yu
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, UK.
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3
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Effect of Ion Concentration on the Electro-Optic Response in Polymer-Stabilized Cholesteric Liquid Crystals. CRYSTALS 2020. [DOI: 10.3390/cryst11010007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have previously reported that the application of a DC field can adjust the position and/or bandwidth of the selective reflection notch in polymer-stabilized cholesteric liquid crystals (PSCLCs). The proposed mechanism of these electro-optic (EO) response is ion-facilitated electromechanical deformation of the polymer stabilizing network. Accordingly, the concentration of ions trapped within the polymer network should considerably influence the EO response of PSCLC. Our prior studies have indicated that photoinitiators can increase ion density in PSCLC by an order of magnitude. Here, we isolate the contribution of ionic impurities associated with liquid crystal monomers (LCMs) by utilizing initiator-less polymerization. PSCLCs prepared with LCM with low ion concentration show bandwidth broadening of the reflection band whereas PSCLCs prepared with LCM with high ion concentration exhibit a red shifting tuning of the reflection band. The extent of the tuning or bandwidth broadening of the CLC reflection band depends on the concentration of LCMs and the chirality of the LCM.
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4
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Potter TD, Walker M, Wilson MR. Self-assembly and mesophase formation in a non-ionic chromonic liquid crystal: insights from bottom-up and top-down coarse-grained simulation models. SOFT MATTER 2020; 16:9488-9498. [PMID: 32955531 DOI: 10.1039/d0sm01157f] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
New coarse-grained models are introduced for a non-ionic chromonic molecule, TP6EO2M, in aqueous solution. The multiscale coarse-graining (MS-CG) approach is used, in the form of hybrid force matching (HFM), to produce a bottom-up CG model that demonstrates self-assembly in water and the formation of a chromonic stack. However, the high strength of binding in stacks is found to limit the transferability of the HFM model at higher concentrations. The MARTINI 3 framework is also tested. Here, a top-down CG model is produced which shows self-assembly in solution in good agreement with atomistic studies and transfers well to higher concentrations, allowing the full phase diagram of TP6EO2M to be studied. At high concentration, both self-assembly of molecules into chromonic stacks and self-organisation of stacks into mesophases occurs, with the formation of nematic (N) and hexagonal (M) chromonic phases. This CG-framework is suggested as a suitable way of studying a range of chromonic-type drug and dye molecules that exhibit complex self-assembly and solubility behaviour in solution.
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Affiliation(s)
- Thomas D Potter
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, DH1 3LE, UK.
| | - Martin Walker
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, DH1 3LE, UK.
| | - Mark R Wilson
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, DH1 3LE, UK.
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5
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Kim HW, Won SH, Kuzmin V, Kim BS, Shin ST. Molecular Ordering Behavior of Lyotropic Chromonic Liquid Crystals on a Polyimide Alignment Layer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5778-5786. [PMID: 32388988 DOI: 10.1021/acs.langmuir.0c00486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Coating-type polarizing films with a high dichroic ratio (DR) and polarization efficiency in the visible region were fabricated using a solution of ternary lyotropic chromonic liquid crystals (LCLCs). Optical characteristics of these anisotropic LCLC polarizing films were then determined. DR increased with increasing LCLC concentrations. Molecular ordering of these LCLCs on a rubbed polyimide (PI) layer increased because LCLC molecules' orientation was enhanced by the dielectric anisotropy effect from rubbing the surface of the PI. In addition, this study demonstrated how the interaction between liquid crystal aggregates and the PI surface with different LCLC solutions correlated with LCLC molecular orientations on the PI which is significantly dependent on whether the coating direction of the LCLC solution was parallel or perpendicular to the PI rubbing direction. It was found that the ordering direction at high LCLC concentrations was determined by shearing direction of the LCLC solution coating, whereas the ordering direction at low LCLC concentrations was governed by the dielectric anisotropy effect from the PI rubbing direction.
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Affiliation(s)
- Hyeong Wook Kim
- Department of Applied Physics, Korea University, 2511, Sejong-ro, Sejong 30019, Republic of Korea
| | - Sang Hee Won
- Department of Applied Physics, Korea University, 2511, Sejong-ro, Sejong 30019, Republic of Korea
| | - Valery Kuzmin
- Light Polymers Inc., 298 Lawrence Avenue, South San Francisco, California 94080, United States
| | - Bo Sung Kim
- Department of Applied Physics, Korea University, 2511, Sejong-ro, Sejong 30019, Republic of Korea
- Light Polymers Inc., 298 Lawrence Avenue, South San Francisco, California 94080, United States
| | - Sung Tae Shin
- Department of Applied Physics, Korea University, 2511, Sejong-ro, Sejong 30019, Republic of Korea
- Light Polymers Inc., 298 Lawrence Avenue, South San Francisco, California 94080, United States
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6
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Matus Rivas OM, Rey AD. Molecular Dynamics Study of the Effect of l-Alanine Chiral Dopants on Diluted Chromonic Solutions. J Phys Chem B 2019; 123:8995-9010. [PMID: 31525883 DOI: 10.1021/acs.jpcb.9b06111] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Atomistic molecular dynamics simulations have been performed for disodium cromoglycate (DSCG) chromonic solutions mixed with l-alanine chiral dopants. We study the fundamental molecular mechanisms induced by low concentrations of l-alanine on diluted DSCG solutions, including their effect on the chromonic aggregates, the solvent, and sodium counterions. Simulations reveal that l-alanine molecules primarily interact with DSCG stacks establishing salt bridges between their respective ammonium and carboxylate groups. Our results demonstrate that l-alanine and sodium counterions jointly establish an intricate network of noncovalent interactions around DSCG aggregates that decreases the global electrostatic repulsion of the chromonic system. Two possible structural effects in DSCG aggregates arise from this electronic stabilization: the increment of the total number of consecutively stacked aromatic planes per DSCG aggregate (intracolumnar effect) or the partial separation reduction between neighboring DSCG columnar sections due to the simultaneous bridging of intercolumnar DSCG carboxylate sites by sodium counterions, forming sodium bridges (intercolumnar effect). Sodium bridges may be responsible for the formation of stacking faults in DSCG aggregates in the form of lateral overlap junctions. This mechanism would explain the difference between lower X-ray correlation lengths with the expected persistence length in chromonics.
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Affiliation(s)
- Oscar M Matus Rivas
- Department of Chemical Engineering , McGill University , Montreal , Quebec H3A 0C5 , Canada
| | - Alejandro D Rey
- Department of Chemical Engineering , McGill University , Montreal , Quebec H3A 0C5 , Canada
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7
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Matus Rivas OM, Rey AD. Effects of Sodium and Magnesium Cations on the Aggregation of Chromonic Solutions Using Molecular Dynamics. J Phys Chem B 2019; 123:1718-1732. [PMID: 30672292 DOI: 10.1021/acs.jpcb.8b12130] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Lyotropic chromonic liquid crystals (LCLCs) constitute a unique variety of water-soluble mesogens that spontaneously assemble into elongated aggregates, thereby resulting in the formation of liquid crystal phases depending on the temperature and concentration. The influence of ionic additives on the aggregation of LCLC has been extensively studied, but the molecular mechanisms governing these effects remain unclear. In this investigation, we perform atomistic molecular dynamics simulations of dilute sunset yellow (SSY) LCLC solutions doped with NaCl and MgCl2 salts. Structural and dynamical properties of SSY hydration shells are considerably modified by the partial substitution of their H bonds with sodium/magnesium-sulfonate ion pairs. Although the intermolecular distance of ∼3.4 Å between SSY mesogens is preserved regardless of the ionic content, the growing number of ion pairs favors the reduction of the electrostatic repulsion between mesogens, increasing the length of SSY stacks. Moreover, magnesium cations exert the strongest electrostatic effects due to their higher hydration capabilities and acute electrostatic binding to SSY. For these reasons, experimental observations of dilute SSY solutions doped with Mg2+ exhibit higher nematic-to-isotropic transition temperatures than Na+. This work provides a fundamental understanding of the influence of ionic additives on the self-assembly of diluted LCLC solutions derived from the synergistic molecular mechanisms between mesogens, the solvent, and cations.
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Affiliation(s)
- Oscar M Matus Rivas
- Department of Chemical Engineering , McGill University , Montreal , Quebec H3A OC5 , Canada
| | - Alejandro D Rey
- Department of Chemical Engineering , McGill University , Montreal , Quebec H3A OC5 , Canada
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8
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Thind R, Walker M, Wilson MR. Molecular Simulation Studies of Cyanine-Based Chromonic Mesogens: Spontaneous Symmetry Breaking to Form Chiral Aggregates and the Formation of a Novel Lamellar Structure. ADVANCED THEORY AND SIMULATIONS 2018. [DOI: 10.1002/adts.201800088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Romnik Thind
- Department of Chemistry; Durham University; Lower Mountjoy, Stockton Road Durham DH1 3LE UK
| | - Martin Walker
- Department of Chemistry; Durham University; Lower Mountjoy, Stockton Road Durham DH1 3LE UK
| | - Mark R. Wilson
- Department of Chemistry; Durham University; Lower Mountjoy, Stockton Road Durham DH1 3LE UK
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9
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Walker M, Wilson MR. Formation of complex self-assembled aggregates in non-ionic chromonics: dimer and trimer columns, layer structures and spontaneous chirality. SOFT MATTER 2016; 12:8588-8594. [PMID: 27722663 DOI: 10.1039/c6sm01669c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Dissipative particle dynamics (DPD) simulations are used to model the aqueous self-assembly of three variants of the non-ionic triphenylene-based chromonic mesogen, TP6EO2M. In the variants studied, one to three of the six methoxy poly(ethylene glycol) chains of TP6EO2M are replaced by short hydrophobic-lipophobic chains, causing a remarkable change in the structure of the mesophases formed. In the 100 wt% limit, corresponding to pure thermotropic phases, complex columnar phases arise, in which the underlying hexagonal packing is supplemented by additional order resulting from microphase separation of hydrophobic-lipophobic regions. With addition of water an array of novel chromonic phases are seen. In these phases supramolecular aggregates form in which hydrophobic-lipophobic chains are excluded from water by the joining together of single molecule chromonic stacks into dimers or trimers. These aggregates form chromonic N and M phases and, in the case of a "Janus mesogen" (with three hydrophobic-lipophobic chains on one side of the molecule), form a novel smectic chromonic phase. Spontaneous symmetry breaking is seen in columns composed of trimer stacks with defects. Here achiral molecular aggregates develop a spontaneous twist, inducing the formation of either left-handed or right-handed chiral aggregates. On the long time-scales accessible to DPD simulations, chiral aggregates are seen to be dynamic structures in which chirality inversion can take place over long periods of time.
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Affiliation(s)
- Martin Walker
- Durham University, Department of Chemistry, Lower Mountjoy, South Road, Durham DH1 3LE, UK.
| | - Mark R Wilson
- Durham University, Department of Chemistry, Lower Mountjoy, South Road, Durham DH1 3LE, UK.
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10
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Lee KM, Ware TH, Tondiglia VP, McBride MK, Zhang X, Bowman CN, White TJ. Initiatorless Photopolymerization of Liquid Crystal Monomers. ACS APPLIED MATERIALS & INTERFACES 2016; 8:28040-28046. [PMID: 27636826 DOI: 10.1021/acsami.6b09144] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Liquid crystal monomers are widely employed in industry to prepare optical compensating films as well as extend or enhance the properties of certain display modes. Because of the thermotropic nature of liquid crystalline materials, polymerization of liquid crystalline monomers (sometimes referred to as reactive mesogens) is often initiated by radical photoinitiation (photopolymerization) of (meth)acrylate functional groups. Here, we report on the initiatorless photopolymerization of commercially available liquid crystalline monomers upon exposure to 365 nm UV light. Initiatorless polymerization is employed to prepare thin films as well as polymer stabilizing networks in mixtures with low-molar-mass liquid crystals. EPR and FTIR confirm radical generation upon exposure to 365 nm light and conversion of the acrylate functional groups. A potential mechanism is proposed, informed by control experiments that indicate that the monomers undergo a type II Norrish mechanism. The initiatorless polymerization of the liquid crystalline monomers yield liquid crystalline polymer networks with mechanical properties that can be equal to those prepared with conventional radical photoinitiators. We demonstrate that initiatorless polymerization of display modes significantly increases the voltage holding ratio, which could result in a reduction in drive voltages in flat-panel televisions and hand-held devices, extending battery life and reducing power consumption.
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Affiliation(s)
- Kyung Min Lee
- Materials and Manufacturing Directorate, Air Force Research Laboratory , Wright-Patterson Air Force Base, Ohio 45433-7750, United States
- Azimuth Corporation, 4027 Colonel Glenn Hwy, Beavercreek, Ohio 45431, United States
| | - Taylor H Ware
- Materials and Manufacturing Directorate, Air Force Research Laboratory , Wright-Patterson Air Force Base, Ohio 45433-7750, United States
- Azimuth Corporation, 4027 Colonel Glenn Hwy, Beavercreek, Ohio 45431, United States
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas 75080, United States
| | - Vincent P Tondiglia
- Materials and Manufacturing Directorate, Air Force Research Laboratory , Wright-Patterson Air Force Base, Ohio 45433-7750, United States
- Azimuth Corporation, 4027 Colonel Glenn Hwy, Beavercreek, Ohio 45431, United States
| | - Matthew K McBride
- Chemical and Biological Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - Xinpeng Zhang
- Chemical and Biological Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - Christopher N Bowman
- Chemical and Biological Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - Timothy J White
- Materials and Manufacturing Directorate, Air Force Research Laboratory , Wright-Patterson Air Force Base, Ohio 45433-7750, United States
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11
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Magana JR, Homs M, Solans C, Obiols-Rabasa M, Salonen LM, Rodríguez-Abreu C. Self-Assembly and Formation of Chromonic Liquid Crystals from the Dyes Quinaldine Red Acetate and Pyronin Y. J Phys Chem B 2016; 120:250-8. [PMID: 26700729 DOI: 10.1021/acs.jpcb.5b10567] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aqueous self-assembly behavior of the dyes Quinaldine red acetate and Pyronin Y in a wide range of concentrations is reported here for the first time. (1)H NMR spectroscopy, polarized-light optical microscopy, and small and wide X-ray scattering were used to get insight into molecular interactions, phase boundaries and aggregate structure. Quinaldine red acetate and Pyronin Y self-organize into unimolecular stacks driven by attractive aromatic interactions. At high concentrations, spatial correlation among the molecular stacks gives rise to nematic liquid crystals in both systems. Quinaldine red acetate additionally produces a rare chromonic O phase built of columnar aggregates with anisotropic cross-section ordered in a rectangular lattice. The O phase changes into a columnar lamellar structure as a result of a temperature-induced phase transition. Results open the possibility of finding chromonic liquid crystals in other commercially available dyes with a similar molecular structure. This would eventually expand the availability of these unique soft materials and thus introduce new applications for marketed dyes.
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Affiliation(s)
- J R Magana
- Instituto de Química Avanzada de Cataluña, Consejo Superior de Investigaciones Científicas (IQAC-CSIC), CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Jordi Girona 18-26, 08034 Barcelona, Spain
| | - M Homs
- Instituto de Química Avanzada de Cataluña, Consejo Superior de Investigaciones Científicas (IQAC-CSIC), CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Jordi Girona 18-26, 08034 Barcelona, Spain
| | - C Solans
- Instituto de Química Avanzada de Cataluña, Consejo Superior de Investigaciones Científicas (IQAC-CSIC), CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Jordi Girona 18-26, 08034 Barcelona, Spain
| | - M Obiols-Rabasa
- Division of Physical Chemistry, Lund University , Getingevägen 60, SE-22241 Lund, Sweden
| | - L M Salonen
- International Iberian Nanotechnology Laboratory , Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
| | - C Rodríguez-Abreu
- International Iberian Nanotechnology Laboratory , Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
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12
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Jeżewski W. Kinetics of aggregation in liquids with dispersed nanoparticles. Phys Chem Chem Phys 2015; 17:8828-35. [PMID: 25745674 DOI: 10.1039/c4cp05401f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The process of attaching molecules of liquid media by dispersed nanoparticles is modeled and numerically studied. The growth rate of the resulting nanoparticle-induced aggregates is determined by assuming the preferential attachment rule according to which the effectiveness of the connection of a new molecular unit to aggregates is determined by their size. It is shown that, depending on a specific functional form of the growth rate, the size distribution of aggregates can display very different shapes, including various multimodal structures. This can explain experimentally obtained complex size distributions of inhomogeneous aggregates appearing as a consequence of the adsorption of molecules by nanoparticles or as a consequence of the self-assembling of active dispersants on surfaces of nanoparticles. The time evolution and the stationarity of the size distribution are also analyzed, gaining an insight into the long-time behavior of systems with dispersed nanoparticles.
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Affiliation(s)
- Wojciech Jeżewski
- Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, Poznań, Poland.
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13
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Van Hecke GR, Karukstis KK, Rayermann S. Deriving binary phase diagrams for chromonic materials in water mixtures via fluorescence spectroscopy: cromolyn and water. Phys Chem Chem Phys 2015; 17:1047-52. [DOI: 10.1039/c4cp03539a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report here the first example of a new and novel method of determining the binary temperature–composition phase diagram of a chromonic material in water using its intrinsic fluorescence.
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14
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Mercado BR, Nieser KJ, Collings PJ. Cooperativity of the assembly process in a low concentration chromonic liquid crystal. J Phys Chem B 2014; 118:13312-20. [PMID: 25365417 DOI: 10.1021/jp510025j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
IR-806 is a near-infrared cyanine dye that undergoes a two-step assembly process in aqueous solutions. The final assemblies orientationally order into a liquid crystal at a very low concentration (∼0.6 wt % at room temperature). While the first step of the assembly process is continuous as the dye concentration or temperature is varied (isodesmic), the second step is more abrupt (cooperative). Because the absorption spectrum of IR-806 changes dramatically during the assembly process, careful equilibrium and kinetic absorption experiments are utilized to examine the details of the cooperative second step. These experiments involve changes in both concentration and temperature, allowing a close thermodynamic analysis of the assembly process. Both equilibrium and kinetic investigations reveal that the assembly process is highly cooperative and can be described by multiple models (for example, nucleation and growth) in the highly cooperative limit. The enthalpy associated with the growth process and the activation energy of the rate-limiting step during disassembly are determined. These findings have significant implications for the structure of the assemblies that form the liquid crystal phase in IR-806.
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Affiliation(s)
- Benjamin R Mercado
- Department of Physics & Astronomy, Swarthmore College , Swarthmore, Pennsylvania 19081, United States
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15
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Agra-Kooijman DM, Singh G, Lorenz A, Collings PJ, Kitzerow HS, Kumar S. Columnar molecular aggregation in the aqueous solutions of disodium cromoglycate. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:062504. [PMID: 25019802 DOI: 10.1103/physreve.89.062504] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Indexed: 05/11/2023]
Abstract
Stack, chimneylike, and threadlike assemblies have previously been proposed for the structure of disodium cromoglycate (DSCG) aggregates in aqueous solutions. The results of the synchrotron x-ray scattering investigations reported here reveal the formation of simple columnar assemblies with π-π stacking at a separation of 3.4 Å between the DSCG molecules. Lateral separation between the assemblies is concentration and temperature dependent, varying from ∼35 to 42 Å in the orientationally ordered nematic (N) phase and from 27 to 32 Å in the columnar or middle (M) phase having long range lateral positional order. The assemblies' length depends on concentration and consists of ∼23 molecules in the N phase, becoming three to ten times larger in the M phase. The scission energy is concentration dependent in the N phase with values ∼7.19 ± 0.14 k_{B}T (15 wt %), 2.73 ± 0.4 k_{B}T (20 wt %), and 3.05 ± 0.2 k_{B}T (25 wt %). Solutions of all concentrations undergo a spinodal decomposition at temperatures above ∼40 °C, resulting in DSCG-rich regions with the M phase and water-rich regions in the N and isotropic phases.
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Affiliation(s)
| | - Gautam Singh
- Department of Physics, Kent State University, Kent, Ohio 44242, USA
| | - Alexander Lorenz
- Department of Chemistry, Berlin Institute of Technology, Strasse des 17. Juni 124, 10623 Berlin, Germany
| | - Peter J Collings
- Department of Physics & Astronomy, Swarthmore College, Swarthmore, Pennsylvania 19081, USA
| | - Heinz-S Kitzerow
- Department of Chemistry, University of Paderborn, Warburger Strasse 100, 33098 Paderborn, Germany
| | - Satyendra Kumar
- Department of Physics, Kent State University, Kent, Ohio 44242, USA
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16
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Jeong J, Han G, Johnson ATC, Collings PJ, Lubensky TC, Yodh AG. Homeotropic alignment of lyotropic chromonic liquid crystals using noncovalent interactions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:2914-20. [PMID: 24559290 DOI: 10.1021/la404893t] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We report on the homeotropic alignment of lyotropic chromonic liquid crystals (LCLCs). Homeotropic anchoring of LCLCs is difficult to achieve, and this challenge has limited development of applications for LCLCs. In this work, homeotropic alignment is achieved using noncovalent interactions between the LCLC molecules and various alignment layers including graphene, parylene films, poly(methyl methacrylate) films, and fluoropolymer films. The LCLC molecules are unique in that they self-assemble via noncovalent interactions in water into elongated aggregates which, in turn, form nematic and columnar liquid crystal (LC) phases. Here we exploit these same noncovalent interactions to induce homeotropic anchoring of the nematic LCLC. Homeotropic alignment is confirmed by polarized optical microscopy and conoscopy. We also report on novel transient stripe textures that occur when an initial flow-induced planar alignment transforms into the equilibrium homeotropic alignment required by boundary conditions. An understanding of this behavior could be important for switching applications.
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Affiliation(s)
- Joonwoo Jeong
- Department of Physics and Astronomy, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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17
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Walker M, Masters AJ, Wilson MR. Self-assembly and mesophase formation in a non-ionic chromonic liquid crystal system: insights from dissipative particle dynamics simulations. Phys Chem Chem Phys 2014; 16:23074-81. [DOI: 10.1039/c4cp03092c] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Results are presented from a dissipative particle dynamics (DPD) simulation of a model non-ionic chromonic system, TP6EO2M, composed of a poly(ethylene glycol) functionalised aromatic (triphenylene) core.
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Affiliation(s)
- Martin Walker
- Department of Chemistry
- Durham University Science Laboratories
- Durham, UK
| | - Andrew J. Masters
- School of Chemical Engineering and Analytical Science
- University of Manchester
- Manchester, UK
| | - Mark R. Wilson
- Department of Chemistry
- Durham University Science Laboratories
- Durham, UK
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18
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Zhang L, Feng G, Zeravcic Z, Brugarolas T, Liu AJ, Lee D. Using shape anisotropy to toughen disordered nanoparticle assemblies. ACS NANO 2013; 7:8043-8050. [PMID: 23971916 DOI: 10.1021/nn403214p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Assemblies of disordered nanoparticles constitute an important class of materials that have numerous applications in energy conversion and storage, electronics, photonics, and sensing. One major roadblock that limits the widespread utilization of disordered nanoparticle assemblies (DNAs) is their poor damage tolerance; they fracture under small loads and, thus, have low toughness. The absence of fundamental understanding on the mechanical behavior and failure mechanism of disordered nanoparticle assemblies makes it even more challenging to develop new strategies to toughen these structures without compromising their mechanical strength. Here we show the formation of shear bands, highly localized regions of mechanical strain that prelude fracture, in disordered assemblies of spherical nanoparticles, which bear striking resemblance to the deformation mechanism of a different class of disordered materials, metallic glasses. We demonstrate that anisotropic nanoparticles greatly suppress shear band formation and toughen nanoparticle packings without sacrificing their strength, implying that tuning constituent anisotropy can be used to enhance toughness in disordered packings of nanoparticles.
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Affiliation(s)
- Lei Zhang
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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Yang S, Wang B, Cui D, Kerwood D, Wilkens S, Han J, Luk YY. Stereochemical Control of Nonamphiphilic Lyotropic Liquid Crystals: Chiral Nematic Phase of Assemblies Separated by Six Nanometers of Aqueous Solvents. J Phys Chem B 2013; 117:7133-43. [DOI: 10.1021/jp401382h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Sijie Yang
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United
States
| | - Bing Wang
- Novartis Institutes for BioMedical Research, Inc., Cambridge, Massachusetts
02139, United States
| | - Dawei Cui
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United
States
| | - Deborah Kerwood
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United
States
| | - Stephan Wilkens
- Department
of Biochemistry and
Molecular Biology, Upstate Medical University, State University of New York, Syracuse, New York 13210, United
States
| | - Junjie Han
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United
States
| | - Yan-Yeung Luk
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United
States
- Department of Biomedical
and
Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
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20
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Jana D, Ghorai BK. Synthesis and aggregation-induced emission properties of tetraphenylethylene-based oligomers containing triphenylethylene moiety. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.10.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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21
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Mills EA, Regan MH, Stanic V, Collings PJ. Large Assembly Formation via a Two-Step Process in a Chromonic Liquid Crystal. J Phys Chem B 2012; 116:13506-15. [DOI: 10.1021/jp306135w] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Elizabeth A. Mills
- Department of Physics & Astronomy, Swarthmore College, Swarthmore, Pennsylvania 19081, United States
| | - Margaret H. Regan
- Department of Physics & Astronomy, Swarthmore College, Swarthmore, Pennsylvania 19081, United States
| | - Vesna Stanic
- Photon Sciences Directorate, Brookhaven National Laboratory, Upton, New York 11973,
United States
| | - Peter J. Collings
- Department of Physics & Astronomy, Swarthmore College, Swarthmore, Pennsylvania 19081, United States
- Department
of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania
19014, United States
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22
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Varghese N, Shetye GS, Bandyopadhyay D, Gobalasingham N, Seo J, Wang JH, Theiler B, Luk YY. Emulsion of aqueous-based nonspherical droplets in aqueous solutions by single-chain surfactants: templated assembly by nonamphiphilic lyotropic liquid crystals in water. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:10797-10807. [PMID: 22726240 DOI: 10.1021/la302396c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Single-chain surfactants usually emulsify and stabilize oily substances into droplets in an aqueous solution. Here, we report a coassembly system, in which single types of anionic or non-ionic surfactants emulsify a class of water-soluble nonamphiphilic organic salts with fused aromatic rings in aqueous solutions. The nonamphiphilic organic salts are in turn promoted to form droplets of water-based liquid crystals (chromonic liquid crystals) encapsulated by single-chain surfactants. The droplets, stabilized against coalescence by encapsulated in a layer (or layers) of single chain surfactants, are of both nonspherical tactoid (elongated ellipsoid with pointy ends) and spherical shapes. The tactoids have an average long axis of ∼9 μm and a short axis of ∼3.5 μm with the liquid crystal aligning parallel to the droplet surface. The spherical droplets are 5-10 μm in diameter and have the liquid crystal aligning perpendicular to the droplet surface and a point defect in the center. Cationic and zwitterionic surfactants studied in this work did not promote the organic salt to form droplets. These results illustrate the complex interplay of self-association and thermodynamic incompatibility of molecules in water, which can cause new assembly behavior, including potential formation of vesicles or other assemblies, from surfactants that usually form only micelles. These unprecedented tactoidal shaped droplets also provide potential for the fabrication of new soft organic microcapsules.
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Affiliation(s)
- Nisha Varghese
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United States
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23
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Kobayashi M, Komiya SI, Maruyama T, Kasahara Y, Hoshi T. A sharp J-band-like electronic absorption peak observed for the chromonic liquid crystal of bisazo dye Ponceau SS in water. MONATSHEFTE FUR CHEMIE 2011. [DOI: 10.1007/s00706-011-0591-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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24
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Chami F, Wilson MR. Molecular order in a chromonic liquid crystal: a molecular simulation study of the anionic azo dye sunset yellow. J Am Chem Soc 2010; 132:7794-802. [PMID: 20469909 DOI: 10.1021/ja102468g] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have carried out a detailed atomic simulation study of molecular order within a chromonic liquid crystalline material (sunset yellow) in aqueous solution. Self-assembly occurs in dilute solutions to form stacked aggregates, which show a preference for head-to-tail stacking and antiparallel dipole order. This feature is independent of solution concentration and aggregate size. Stacks are found to be dynamic entities in which rotational transitions (flips) can occur between antiparallel and parallel configurations. At a concentration matching the nematic phase of sunset yellow, the simulations show chromonic columns with a loose hexagonal packing and an intercolumn distance of 2.36 nm. Partial condensation of sodium ions occurs around a chromonic stack, with two preferred binding sites identified for sodium ions, corresponding to strong binding with the oxygens of a sulfonate group and a bridging site between a pair of molecules in a stack. A value for the free energy of binding of a molecule to a stack of 7 k(B)T was obtained for stacks of three and eight molecules, with a slightly larger value (additional 2 kJ mol(-1)) obtained for the dimer binding energy, indicating that aggregation is approximately isodesmic.
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Affiliation(s)
- Fatima Chami
- Department of Chemistry, Durham University Science Laboratories, South Road, Durham DH1 3LE, UK
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25
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Renshaw MP, Day IJ. NMR Characterization of the Aggregation State of the Azo Dye Sunset Yellow in the Isotropic Phase. J Phys Chem B 2010; 114:10032-8. [DOI: 10.1021/jp104356m] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Matthew P. Renshaw
- Department of Chemistry and Biochemistry, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QJ, U.K
| | - Iain J. Day
- Department of Chemistry and Biochemistry, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QJ, U.K
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26
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McKitterick CB, Erb-Satullo NL, LaRacuente ND, Dickinson AJ, Collings PJ. Aggregation Properties of the Chromonic Liquid Crystal Benzopurpurin 4B. J Phys Chem B 2010; 114:1888-96. [DOI: 10.1021/jp910136p] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christopher B. McKitterick
- Department of Physics & Astronomy, Swarthmore College, Swarthmore, Pennsylvania 19081, and Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19014
| | - Nathaniel L. Erb-Satullo
- Department of Physics & Astronomy, Swarthmore College, Swarthmore, Pennsylvania 19081, and Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19014
| | - Nicholas D. LaRacuente
- Department of Physics & Astronomy, Swarthmore College, Swarthmore, Pennsylvania 19081, and Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19014
| | - Alexandra J. Dickinson
- Department of Physics & Astronomy, Swarthmore College, Swarthmore, Pennsylvania 19081, and Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19014
| | - Peter J. Collings
- Department of Physics & Astronomy, Swarthmore College, Swarthmore, Pennsylvania 19081, and Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19014
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27
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28
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Bertrand CE, Linegar KL, Kostko AF, Anisimov MA. Multiscale dynamics of pretransitional fluctuations in the isotropic phase of a lyotropic liquid crystal. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:041704. [PMID: 19518247 DOI: 10.1103/physreve.79.041704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Revised: 12/18/2008] [Indexed: 05/27/2023]
Abstract
Using an improved static and dynamic light-scattering technique, we have observed multiscale relaxation of the pretransitional fluctuations in the isotropic phase of a cromolyn aqueous solution, a lyotropic liquid crystal where rods are formed by aggregates of disklike molecules. We have detected the onset of cromolyn aggregation about 12 degrees C above the transition temperature. The onset is manifested by the emergence of strong scattering due to the fluctuations of local anisotropy and by the split of the diffusion dynamics into two distinctly different modes, one associated with the relatively fast diffusion of monomer-size particles and the other one with the much slower diffusion of the cromolyn aggregates. A third observed dynamic mode is associated with the pretransitional slowing down of fluctuations of the local anisotropy. This mode behaves differently in polarized and depolarized light scattering, due to a coupling between fluctuations of the local-anisotropy and velocity fluctuations.
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Affiliation(s)
- C E Bertrand
- Department of Chemical and Biomolecular Engineering and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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