1
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Aya S, Tang W, Kong X, Arakawa Y, Komatsu K, Tsuji H. Nontrivial ultraslow dynamics under electric-field in nematics of bent-shaped molecules. Phys Chem Chem Phys 2022; 25:297-303. [PMID: 36477024 DOI: 10.1039/d2cp02407a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
For over decades, nematic liquid crystals have been recognized as highly fluidic materials that respond to electric field on the millisecond scale. In contrast to traditional nematics with fast responsivity, we herein report nontrivial ultraslow electric-driven dynamics in bent-shaped nematic materials. Varying the alkyl chain spacers of bent-shaped cyanobiphenyl dimers (COOm and OCOm) shows a 'transition' in the dynamics behavior between the bent-dimeric and bent-core materials. Interestingly, with short alkyl chain spacers, COO2 exhibits unexpected ultra-slow dynamic pathways, i.e., "quasi-static" electrohydrodynamic convection. A significant observation is that the on/off-electro-switching time of COO2 is 10 000 times higher than that of typical nematic materials, which is the largest value reported ever in the kilo-second range. In addition, the threshold voltage for inducing the reorientation of the nematic director for COO2 is higher than 5 V, which is uncommon in traditional N materials. These properties are distinct from those of traditional nematic materials and discussed in terms of dielectric constants and electrohydrodynamic convection.
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Affiliation(s)
- Satoshi Aya
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China. .,Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Wentao Tang
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China.
| | - Xian Kong
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China.
| | - Yuki Arakawa
- Department of Applied Chemistry and Life Science, Graduate School of Engineering, Toyohashi University of Technology, Toyohashi, 441-8580, Japan.
| | - Kenta Komatsu
- Department of Applied Chemistry and Life Science, Graduate School of Engineering, Toyohashi University of Technology, Toyohashi, 441-8580, Japan.
| | - Hideto Tsuji
- Department of Applied Chemistry and Life Science, Graduate School of Engineering, Toyohashi University of Technology, Toyohashi, 441-8580, Japan.
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2
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Ilyin SO, Konstantinov II. Rheology of highly ordered smectic phases based on biphenyl derivatives. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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3
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Electric-field-induced patterns in a hockey-stick nematic. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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4
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Hamdi R. Synthesis and physicochemical studies of double fluorinated hydrogen-bonded liquid crystals (n-OBAFF). J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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5
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Abstract
Smart soft materials are envisioned to be the building blocks of the next generation of advanced devices and digitally augmented technologies. In this context, liquid crystals (LCs) owing to their responsive and adaptive attributes could serve as promising smart soft materials. LCs played a critical role in revolutionizing the information display industry in the 20th century. However, in the turn of the 21st century, numerous beyond-display applications of LCs have been demonstrated, which elegantly exploit their controllable stimuli-responsive and adaptive characteristics. For these applications, new LC materials have been rationally designed and developed. In this Review, we present the recent developments in light driven chiral LCs, i.e., cholesteric and blue phases, LC based smart windows that control the entrance of heat and light from outdoor to the interior of buildings and built environments depending on the weather conditions, LC elastomers for bioinspired, biological, and actuator applications, LC based biosensors for detection of proteins, nucleic acids, and viruses, LC based porous membranes for the separation of ions, molecules, and microbes, living LCs, and LCs under macro- and nanoscopic confinement. The Review concludes with a summary and perspectives on the challenges and opportunities for LCs as smart soft materials. This Review is anticipated to stimulate eclectic ideas toward the implementation of the nature's delicate phase of matter in future generations of smart and augmented devices and beyond.
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Affiliation(s)
- Hari Krishna Bisoyi
- Advanced Materials and Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, United States
| | - Quan Li
- Advanced Materials and Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, United States.,Institute of Advanced Materials, School of Chemistry and Chemical Engineering, and Jiangsu Hi-Tech Key Laboratory for Biomedical Research, Southeast University, Nanjing 211189, China
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6
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Pristine and ferroelectric liquid crystal dispersed four ring bent core nematic: Impact of dispersion on electro-optic and dielectric properties. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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7
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Asiya S, Pal K, El-Sayyad GS, Elkodous MA, Demetriades C, Kralj S, Thomas S. Reliable optoelectronic switchable device implementation by CdS nanowires conjugated bent-core liquid crystal matrix. ORGANIC ELECTRONICS 2020; 82:105592. [DOI: 10.1016/j.orgel.2019.105592] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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8
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Punjani V, Mohiuddin G, Kaur S, Choudhury AR, Paladugu S, Dhara S, Ghosh S, Pal SK. Chiral Bent-Shaped Molecules Exhibiting Unusually Wide Range of Blue Liquid-Crystalline Phases and Multistimuli-Responsive Behavior. Chemistry 2020; 26:5859-5871. [PMID: 32083772 DOI: 10.1002/chem.201905707] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/02/2020] [Indexed: 11/11/2022]
Abstract
Recently, an unprecedented observation of polar order, thermochromic behavior, and exotic mesophases in new chiral, bent-shaped systems with a -CH3 moiety placed at the transverse position of the central core was reported. Herein, a homologous series of compounds with even-numbered carbon chains from n=4 to 18 were synthesized, in which -Cl was substituted for -CH3 at the kink position and a drastic modification in the phase structure of the bent-shaped molecule was observed. An unusual stabilization of the cubic blue phase (BP) over a wide range of 16.4 °C has been witnessed. Two homologues in this series (1-12 and 1-14) exhibit an interesting phase sequence consisting of BPI/II, chiral nematic, twist grain boundary, smectic A, and smectic X (SmX) phases. The higher homologues (1-16 and 1-18) stabilize the SmX phase enantiotropically over the entire temperature range. Crystal structure analysis confirmed the bent molecular architecture, with a bent angle of 148°, and revealed the presence of two different molecular conformations in an asymmetric unit of compound 1-4. A DFT study corroborated that the -Cl moiety at the central core of the molecule led to an increase in the dipole moment along the transverse direction, which, in turn, facilitated the unusual stabilization of frustrated structures. Crystal polymorphism has been evidenced in three homologues (1-10, 1-12, and 1-14) of the series. On the application of mechanical pressure through grinding, compound 1-10 transformed from a bright yellow crystalline solid to a dark orange-green amorphous solid, which reversed upon dropwise addition of dichloromethane, indicating reversible mechanochromism in this class of compounds. In addition, excellent thermochromic behavior has been observed for compound 1-10 with a controlled temperature-color combination.
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Affiliation(s)
- Vidhika Punjani
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Knowledge City, Manauli, 140306, India
| | - Golam Mohiuddin
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Knowledge City, Manauli, 140306, India
| | - Supreet Kaur
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Knowledge City, Manauli, 140306, India
| | - Angshuman Roy Choudhury
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Knowledge City, Manauli, 140306, India
| | | | - Surajit Dhara
- School of Physics, University of Hyderabad, Hyderabad, 500046, India
| | - Sharmistha Ghosh
- Department of Physics, University of Calcutta, 92 Acharyya Prafulla Chandra Road, Kolkata, 700009, India
| | - Santanu Kumar Pal
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Knowledge City, Manauli, 140306, India
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9
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Missaoui T, Ben Amor I, Soltani T, Ben Ouada H, Jeanneau E, Chevalier Y. Dielectric and electro-optic properties of cybotactic nematic phase in hydrogen-bonded liquid crystals. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.112726] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Nematic and switchable intercalated phases in polymerizable bent-core monomers with naphthalene moiety in the side arms of the aromatic core. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2019.126971] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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11
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Kaur S, Mohiuddin G, Punjani V, Khan RK, Ghosh S, Pal SK. Structural organization and molecular self-assembly of a new class of polar and non-polar four-ring based bent-core molecules. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111687] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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12
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Westphal E, Gallardo H, Poppe S, Prehm M, Tschierske C. Controlling the soft self-assembly of 1,3,4-oxadiazoles by carbosilane end-groups. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111362] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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13
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Reshetnyak VY, Pinkevych IP, Evans DR. Flexoelectro-optic effect and two-beam energy exchange in a hybrid photorefractive cholesteric cell with a short-pitch horizontal helix. Phys Rev E 2018; 97:062701. [PMID: 30011427 DOI: 10.1103/physreve.97.062701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Indexed: 11/07/2022]
Abstract
We develop a theoretical model to describe two-beam energy exchange in a hybrid photorefractive cholesteric cell with a short-pitch helix oriented parallel to the cell substrates (so-called uniformly lying helix configuration). Weak and strong light beams incident on the hybrid cell interfere and induce a periodic space-charge field in the photorefractive substrate of the cell, which penetrates into the cholesteric liquid crystal (LC). Due to the flexoelectro-optic effect an interaction of the photorefractive field with the LC flexopolarization causes the spatially periodic modulation of the helix axis in the plane parallel to the cell substrates. Coupling of a weak signal beam with a strong pump beam at the LC permittivity grating, induced by the periodically tilted helix axis, leads to the energy gain of the weak signal beam. Dependence of the signal beam gain coefficient on the parameters of the short-pitch cholesteric LC is studied.
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Affiliation(s)
- V Yu Reshetnyak
- Physics Faculty, Taras Shevchenko National University of Kyiv, Volodymyrska Street 64, Kyiv 01601, Ukraine
| | - I P Pinkevych
- Physics Faculty, Taras Shevchenko National University of Kyiv, Volodymyrska Street 64, Kyiv 01601, Ukraine
| | - D R Evans
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, USA
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14
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Kumar P, Debnath S, Rao NVS, Sinha A. Nanodoping: a route for enhancing electro-optic performance of bent core nematic system. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:095101. [PMID: 29336349 DOI: 10.1088/1361-648x/aaa801] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report the effect of dispersion of barium titanate (BaTiO3) nanoparticles (BNPs) in a four ring bent core nematic (BCN) liquid crystal. Polarizing optical microscopy reveals the presence of a single nematic phase in pure and doped states. Polar switching has been observed in the bent core system and the value of spontaneous polarization (P s) increases with increase in doping concentration of BNPs in BCN. Dielectric study shows a lower frequency mode, which can be ascribed to the formation of cybotactic clusters. These clusters are also responsible for the observed polar switching in pure, as well as, in doped BCNs. Another higher frequency mode, observed only in pure BCN, indicates the rotation of molecules about their long molecular axis. The conductivity of doped samples is also found to decrease as compared to the pure BCN. This reduction helps in the minimization of negative effects caused by free ions in liquid crystal based devices. This study demonstrates that the interaction between BNPs and BCN molecules improves the P s, dielectric behaviour, viscosity and reduces the conductivity of pure BCN. Hence, nanodoping in a BCN is an effective method for the enhancement of electro-optic performances and will lead to the development of faster electro-optic devices.
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Affiliation(s)
- Pradeep Kumar
- Department of Physics, Indian Institute of Technology Delhi, 110016, India
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15
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Khan RK, Turlapati S, Begum N, Mohiuddin G, Rao NS, Ghosh S. Impact of terminal polar substitution on elastic, electro-optic and dielectric properties of four-ring bent-core nematic liquid crystals. RSC Adv 2018; 8:11509-11516. [PMID: 35542808 PMCID: PMC9079133 DOI: 10.1039/c8ra00575c] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/18/2018] [Indexed: 11/21/2022] Open
Abstract
Here we report the influence of terminal –F, –Cl and –NO2 substitution on the elastic, dielectric and polar switching behavior of four-ring bent-core liquid crystals (LCs).
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Affiliation(s)
- R. K. Khan
- Department of Physics
- University of Calcutta
- Kolkata 700 009
- India
| | - S. Turlapati
- Chemistry Department
- Assam University
- Silchar 788011
- India
| | - N. Begum
- Chemistry Department
- Assam University
- Silchar 788011
- India
| | - G. Mohiuddin
- Chemistry Department
- Assam University
- Silchar 788011
- India
| | - N. V. S. Rao
- Chemistry Department
- Assam University
- Silchar 788011
- India
| | - S. Ghosh
- Department of Physics
- University of Calcutta
- Kolkata 700 009
- India
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16
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Liu K, Greitemann J, Pollet L. Generic first-order phase transitions between isotropic and orientational phases with polyhedral symmetries. Phys Rev E 2018; 97:012706. [PMID: 29448474 DOI: 10.1103/physreve.97.012706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Indexed: 06/08/2023]
Abstract
Polyhedral nematics are examples of exotic orientational phases that possess a complex internal symmetry, representing highly nontrivial ways of rotational symmetry breaking, and are subject to current experimental pursuits in colloidal and molecular systems. The classification of these phases has been known for a long time; however, their transitions to the disordered isotropic liquid phase remain largely unexplored, except for a few symmetries. In this work, we utilize a recently introduced non-Abelian gauge theory to explore the nature of the underlying nematic-isotropic transition for all three-dimensional polyhedral nematics. The gauge theory can readily be applied to nematic phases with an arbitrary point-group symmetry, including those where traditional Landau methods and the associated lattice models may become too involved to implement owing to a prohibitive order-parameter tensor of high rank or (the absence of) mirror symmetries. By means of exhaustive Monte Carlo simulations, we find that the nematic-isotropic transition is generically first-order for all polyhedral symmetries. Moreover, we show that this universal result is fully consistent with our expectation from a renormalization group approach, as well as with other lattice models for symmetries already studied in the literature. We argue that extreme fine tuning is required to promote those transitions to second-order ones. We also comment on the nature of phase transitions breaking the O(3) symmetry in general cases.
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Affiliation(s)
- Ke Liu
- Arnold Sommerfeld Center for Theoretical Physics, University of Munich, Theresienstrasse 37, 80333 Munich, Germany
| | - Jonas Greitemann
- Arnold Sommerfeld Center for Theoretical Physics, University of Munich, Theresienstrasse 37, 80333 Munich, Germany
| | - Lode Pollet
- Arnold Sommerfeld Center for Theoretical Physics, University of Munich, Theresienstrasse 37, 80333 Munich, Germany
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17
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Gowda A, Jacob L, Joy N, Philip R, R P, Kumar S. Thermal and nonlinear optical studies of newly synthesized EDOT based bent-core and hockey-stick like liquid crystals. NEW J CHEM 2018. [DOI: 10.1039/c7nj04807f] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis and characterisation of novel bent-core and hockey-stick like liquid crystals from EDOT are reported. All the compounds exhibit an enantiotropic mesophase with a wide temperature range. These mesogens show good photophysical and nonlinear optical properties.
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Affiliation(s)
| | - Litwin Jacob
- Raman Research Institute
- Bangalore – 560 080
- India
| | - Nithin Joy
- Raman Research Institute
- Bangalore – 560 080
- India
| | - Reji Philip
- Raman Research Institute
- Bangalore – 560 080
- India
| | - Pratibha R
- Raman Research Institute
- Bangalore – 560 080
- India
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18
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Babakhanova G, Parsouzi Z, Paladugu S, Wang H, Nastishin YA, Shiyanovskii SV, Sprunt S, Lavrentovich OD. Elastic and viscous properties of the nematic dimer CB7CB. Phys Rev E 2017; 96:062704. [PMID: 29347367 DOI: 10.1103/physreve.96.062704] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Indexed: 05/16/2023]
Abstract
We present a comprehensive set of measurements of optical, dielectric, diamagnetic, elastic, and viscous properties in the nematic (N) phase formed by a liquid crystalline dimer. The studied dimer, 1,7-bis-4-(4'-cyanobiphenyl) heptane (CB7CB), is composed of two rigid rodlike cyanobiphenyl segments connected by a flexible aliphatic link with seven methyl groups. CB7CB and other nematic dimers are of interest due to their tendency to adopt bent configurations and to form two states possessing a modulated nematic director structure, namely, the twist-bend nematic, N_{TB}, and the oblique helicoidal cholesteric, Ch_{OH}, which occurs when the achiral dimer is doped with a chiral additive and exposed to an external electric or magnetic field. We characterize the material parameters as functions of temperature in the entire temperature range of the N phase, including the pretransitional regions near the N-N_{TB} and N-to-isotropic (I) transitions. The splay constant K_{11} is determined by two direct and independent techniques, namely, detection of the Frederiks transition and measurement of director fluctuation amplitudes by dynamic light scattering (DLS). The bend K_{33} and twist K_{22} constants are measured by DLS. K_{33}, being the smallest of the three constants, shows a strong nonmonotonous temperature dependence with a negative slope in both N-I and N-N_{TB} pretransitional regions. The measured ratio K_{11}/K_{22} is larger than 2 in the entire nematic temperature range. The orientational viscosities associated with splay, twist, and bend fluctuations in the N phase are comparable to those of nematics formed by rodlike molecules. All three show strong temperature dependence, increasing sharply near the N-N_{TB} transition.
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Affiliation(s)
- Greta Babakhanova
- Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA
- Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, USA
| | - Zeinab Parsouzi
- Department of Physics, Kent State University, Kent, Ohio 44242, USA
| | | | - Hao Wang
- Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA
- Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, USA
| | - Yu A Nastishin
- Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA
- Hetman Petro Sahaidachnyi National Army Academy, 32, Heroes of Maidan Street, Lviv 79012, Ukraine
| | | | - Samuel Sprunt
- Department of Physics, Kent State University, Kent, Ohio 44242, USA
| | - Oleg D Lavrentovich
- Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA
- Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, USA
- Department of Physics, Kent State University, Kent, Ohio 44242, USA
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19
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Unsymmetrical achiral four ring hockey stick shaped mesogens based on 1,3,4-oxadiazole: Photophysical, mesogenic and DFT studies. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.06.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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20
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Singh S, Singh H, Tandon P, Chakraborty N, Rao NVS, Ayala AP. Study of Cr→SmA phase transition and hydrogen bonding in four-ring bent-core liquid crystal. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 178:142-150. [PMID: 28182984 DOI: 10.1016/j.saa.2017.01.067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 01/21/2017] [Accepted: 01/27/2017] [Indexed: 06/06/2023]
Abstract
A newly designed asymmetrical four-ring bent-core compound (4'-n-decyloxyphenylazo)-phenyl-4-yl-3-[N-(4'-n-octadecyloxy-2-hydroxybenzylidene) amino]-2-methyl benzoate exhibiting liquid crystalline behavior was synthesized and characterized. The thermal and textural morphology were studied using differential scanning calorimetry and polarizing optical microscopy, respectively. The study of hydrogen bonding and dynamics of the phase transition has been performed at the molecular level using temperature dependent Fourier transform infrared (FTIR) spectroscopy. The spectral analysis of OH, CH2/CH3, CO, and CN stretching vibrational bands revealed clear signatures of Cr→SmA phase transition at 125°C. Density functional theory has been adopted for the geometry optimization and conformational study of the monomer using the B3LYP/6-31G(d) method. The conformational analysis has been performed to predict the most stable conformer along with the possible conformers using one-dimensional potential energy scan employing the same level of theory. The combination of experimental findings and theoretical analysis helped to understand the mechanism of phase transitions at the molecular level.
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Affiliation(s)
- Swapnil Singh
- Department of Physics, University of Lucknow, Lucknow 226007, India
| | - Harshita Singh
- Department of Physics, University of Lucknow, Lucknow 226007, India
| | - Poonam Tandon
- Department of Physics, University of Lucknow, Lucknow 226007, India.
| | | | - N V S Rao
- Chemistry Department, Assam University, Silchar 788011, Assam, India
| | - A P Ayala
- Departamento de Física, Universidade Federal do Ceará, C.P. 6030, 60.455-900 Fortaleza, CE, Brazil
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21
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Gowda A, Roy A, Kumar S. Synthesis and mesomorphic properties of novel Schiff base liquid crystalline EDOT derivatives. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2016.11.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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22
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Kaur S, Punjani V, Mohiuddin G, Pal SK. Orthogonal smectic and nematic ordering in three-ring polar bent-core molecules with anti-parallel arrangement. NEW J CHEM 2017. [DOI: 10.1039/c7nj00272f] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three-ring based BLCs exhibiting orthogonal smectic and nematic phases with antiparallel arrangement as derived from SCXRD and X-ray scattering results.
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Affiliation(s)
- Supreet Kaur
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Mohali
- Manauli-140306
- India
| | - Vidhika Punjani
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Mohali
- Manauli-140306
- India
| | - Golam Mohiuddin
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Mohali
- Manauli-140306
- India
| | - Santanu Kumar Pal
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Mohali
- Manauli-140306
- India
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23
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Bisoyi HK, Li Q. Light-Driven Liquid Crystalline Materials: From Photo-Induced Phase Transitions and Property Modulations to Applications. Chem Rev 2016; 116:15089-15166. [PMID: 27936632 DOI: 10.1021/acs.chemrev.6b00415] [Citation(s) in RCA: 407] [Impact Index Per Article: 50.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Light-driven phenomena both in living systems and nonliving materials have enabled truly fascinating and incredible dynamic architectures with terrific forms and functions. Recently, liquid crystalline materials endowed with photoresponsive capability have emerged as enticing systems. In this Review, we focus on the developments of light-driven liquid crystalline materials containing photochromic components over the past decade. Design and synthesis of photochromic liquid crystals (LCs), photoinduced phase transitions in LC, and photoalignment and photoorientation of LCs have been covered. Photomodulation of pitch, polarization, lattice constant and handedness inversion of chiral LCs is discussed. Light-driven phenomena and properties of liquid crystalline polymers, elastomers, and networks have also been analyzed. The applications of photoinduced phase transitions, photoalignment, photomodulation of chiral LCs, and photomobile polymers have been highlighted wherever appropriate. The combination of photochromism, liquid crystallinity, and fabrication techniques has enabled some fascinating functional materials which can be driven by ultraviolet, visible, and infrared light irradiation. Nanoscale particles have been incorporated to widen and diversify the scope of the light-driven liquid crystalline materials. The developed materials possess huge potential for applications in optics, photonics, adaptive materials, nanotechnology, etc. The challenges and opportunities in this area are discussed at the end of the Review.
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Affiliation(s)
- Hari Krishna Bisoyi
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University , Kent, Ohio 44242, United States
| | - Quan Li
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University , Kent, Ohio 44242, United States
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Nafees A, Sinha A, Rao NVS, Kalita G, Mohiuddin G, Paul MK. Design, synthesis and mesomorphic behaviour of a four-ring achiral bent-core liquid crystal in the nematic phase. RSC Adv 2016. [DOI: 10.1039/c6ra05125a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Design, synthesis and characterization of a four-ring achiral bent-core liquid crystal with a broad range nematic phase which can be cooled down without crystallization.
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Affiliation(s)
- Amina Nafees
- Department of Physics
- Indian Institute of Technology Delhi
- New Delhi-110016
- India
| | - Aloka Sinha
- Department of Physics
- Indian Institute of Technology Delhi
- New Delhi-110016
- India
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25
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Sreenilayam SP, Panarin YP, Vij JK, Torgova SI, Lehmann A, Tschierske C. Flexoelectric polarization studies in bent-core nematic liquid crystals. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:022502. [PMID: 26382418 DOI: 10.1103/physreve.92.022502] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Indexed: 06/05/2023]
Abstract
The flexoelectric polarization (Pf) of four bent-core nematic liquid crystals (LCs) has been measured using the pyroelectric effect. Hybrid aligned nematic cells are fabricated for measuring the pyroelectric response over the entire range of the nematic phase. It is found that the magnitude of flexoelectric polarization Pf and the sum of the flexoelectric coefficients |e1+e3| for the bent-core LCs studied here are three to six times higher than for the calamitics. Pf is found to depend on the transverse dipole moment of LC molecules. However, |e1+e3| values are by no means giant as |e3| alone had been reported for a bent-core nematic system previously. The dependence of the sum of "splay and bend flexoelectric coefficients" is discussed in terms of the shape of the molecule and of the dipole moment directed normal to the molecular axis.
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Affiliation(s)
- S P Sreenilayam
- Department of Electronic and Electrical Engineering, Trinity College, University of Dublin, Dublin 2, Ireland
| | - Yu P Panarin
- Department of Electronic and Electrical Engineering, Trinity College, University of Dublin, Dublin 2, Ireland
- School of Electrical and Electronic Engineering, Dublin Institute of Technology, Dublin 8, Ireland
| | - J K Vij
- Department of Electronic and Electrical Engineering, Trinity College, University of Dublin, Dublin 2, Ireland
| | - S I Torgova
- P. N. Lebedev Physical Institute of Russian Academy of Sciences, Moscow, Russia
| | - A Lehmann
- Institute of Chemistry, Martin-Luther-University, Halle-Wittenberg, 06120 Halle, Germany
| | - C Tschierske
- Institute of Chemistry, Martin-Luther-University, Halle-Wittenberg, 06120 Halle, Germany
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26
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Mohiuddin G, Punjani V, Pal SK. Three-Ring-Based Room-Temperature Bent-Core Nematic Compounds: Synthesis and Characterization. Chemphyschem 2015. [DOI: 10.1002/cphc.201500435] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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27
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Nagaraj M, Jones JC, Panov VP, Liu H, Portale G, Bras W, Gleeson HF. Understanding the unusual reorganization of the nanostructure of a dark conglomerate phase. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:042504. [PMID: 25974513 DOI: 10.1103/physreve.91.042504] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Indexed: 06/04/2023]
Abstract
The dark conglomerate (DC) phase exhibited by a bent-core liquid crystal shows remarkable properties including an electric-field tunable chiral domain structure and a large (0.045) reduction of refractive index, while maintaining an optically dark texture when observed under crossed polarizers. A detailed investigation of the system is presented, leading to a model that is fully consistent with the experimental observations. It reports the observation of two distinct regimes in the DC phase: a higher temperature regime in which the periodicity measured by small angle x-ray scattering decreases slightly (0.5%) and a lower temperature regime where it increases considerably (16%). Also, the paper discusses the unusual electric-field-induced transformations observed in both the regimes. These changes have threshold fields that are both temperature and frequency dependent, though the phenomena are observed irrespective of device thickness, geometry, and the alignment layer. The electro-optic behavior in the DC phase corresponds to a number of structural changes leading to unusual changes in physical properties including a small (1%) increase in periodicity and a doubling of the average dielectric permittivity. We propose a model of the DC phase where in the ground state the nanostructure of the phase exhibits an anticlinic antiferroelectric organization. Under an electric field, it undergoes a molecular rearrangement without any gross structural changes leading to an anticlinic ferroelectric order while keeping the overall sponge-like structure of the DC phase intact.
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Affiliation(s)
- M Nagaraj
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - J C Jones
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - V P Panov
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - H Liu
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - G Portale
- DUBBLE Beamline, ESRF, Grenoble 38043, France
| | - W Bras
- DUBBLE Beamline, ESRF, Grenoble 38043, France
| | - H F Gleeson
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
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28
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Tamura K, Yoshida J, Taniguchi M, Kitazawa T, Yamagishi A, Sato H. Effects of auxiliary ligands of Pd(ii) dimers on induction of chiral nematic phases: chirality inversion and the photo-responsive structural change. Dalton Trans 2015; 44:3209-15. [DOI: 10.1039/c4dt02812k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An axially chiral Pd(ii) dimer changed its CD spectrum reversibly under irradiation at either 350 nm or 460 nm when it was doped in liquid crystals.
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Affiliation(s)
- Kenji Tamura
- National Institute of Materials Science
- Tsukuba 305-0044
- Japan
| | - Jun Yoshida
- Department of Chemistry
- School of Science
- Kitasato University
- Sagamihara
- Japan
| | | | - Takafumi Kitazawa
- Department of Chemistry
- Toho University
- Funabashi, Chiba 274-8510
- Japan
| | - Akihiko Yamagishi
- Department of Chemistry
- Toho University
- Funabashi, Chiba 274-8510
- Japan
| | - Hisako Sato
- Department of Chemistry
- Graduate School of Science and Engineering
- Ehime University
- Matsuyama 790-8577
- Japan
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