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Iqbal A, Urbanska M, Dąbrowski RS, Kumar S, Dhar R. Impact of carbon quantum dots on self-assembly and dielectric relaxation modes of a room temperature tri-component fluorinated antiferroelectric liquid crystal mixture. SOFT MATTER 2023; 19:9293-9307. [PMID: 38009790 DOI: 10.1039/d3sm01226c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
We investigated the impact of carbon quantum dots (CQDs) of sizes ∼2-5 nm in a room temperature tri-component fluorinated antiferroelectric liquid crystal (AFLC) mixture. The synthesised CQDs have been characterised by high-resolution transmission electron microscopy and X-ray diffraction spectroscopy. An increase in the transition temperature and enthalpy to the isotropic liquid phase indicates stabilization of the AFLC mixture in the presence of CQDs. The dielectric studies have been carried out in the frequency range of 1 Hz-40 MHz under the planar anchoring conditions of the molecules. An appreciable increase in the permittivity, dielectric strength, and conductivity has been observed owing to the existence of sp2/sp3 hybridization in the CQDs which form a strong coupling and develop a dipolar ordering in the systems. Various relaxation frequencies were increased with the incarceration of CQDs in the AFLC mixture. Overall, the different studies suggest that the doped CQDs are very well settled in between the host molecules without disturbing the molecular ordering of the hosts. Such results are encouraging and reveal the potential applicability of the CQD doped systems to produce highly efficient tuneable optical devices and other multifaceted applications.
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Affiliation(s)
- Amir Iqbal
- Soft Materials Research Laboratory, Centre of Material Sciences, Institute of interdisciplinary Studies, University of Allahabad, Allahabad-211002, India.
| | - Magdalena Urbanska
- Institute of Applied Sciences and Chemistry, Military University of Technology, Warsaw 00-908, Poland
| | - Roman S Dąbrowski
- Institute of Applied Sciences and Chemistry, Military University of Technology, Warsaw 00-908, Poland
| | - Sandeep Kumar
- Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bengaluru 560080, India
- Department of Chemistry, Nitte Meenakshi Institute of Technology, Bengaluru 560064, India
| | - Ravindra Dhar
- Soft Materials Research Laboratory, Centre of Material Sciences, Institute of interdisciplinary Studies, University of Allahabad, Allahabad-211002, India.
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Yamada S, Konno T. Development of Donor-π-Acceptor-Type Fluorinated Tolanes as Compact Condensed Phase Luminophores and Applications in Photoluminescent Liquid-Crystalline Molecules. CHEM REC 2023; 23:e202300094. [PMID: 37098883 DOI: 10.1002/tcr.202300094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/13/2023] [Indexed: 04/27/2023]
Abstract
Fluorinated tolanes, produced by introducing fluorine atoms into one of the aromatic rings of tolane, emitted almost no fluorescence in a solution state, but the fluorescence intensity increased dramatically in the crystalline state because of intermolecular H⋅⋅⋅F hydrogen bonds. The photoluminescent (PL) colors depend on the molecular orbitals, dipole moments, and molecular aggregated structures can be varied by controlling terminal substituents along the major molecular axis. The introduction of a long alkoxy or semifluoroalkoxy unit as a flexible chain into the terminal positions along the major molecular axis induced the formation of a liquid-crystalline (LC) phase; fluorinated tolanes act both as luminophores and as mesogens, leading to the molecular design of new photoluminescent LC molecules (PLLCs). The results also indicated that a fluorinated tolane dimer, which consists of two fluorinated tolanes linked by a flexible alkylene spacer, also becomes a novel PLLC.
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Affiliation(s)
- Shigeyuki Yamada
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Tsutomu Konno
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
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Yamada S, Yoshida K, Kataoka M, Hara M, Konno T. Donor-π-Acceptor-Type Fluorinated Tolane Containing a Semifluoroalkoxy Chain as a Condensed-Phase Luminophore. Molecules 2023; 28:molecules28062764. [PMID: 36985736 PMCID: PMC10055744 DOI: 10.3390/molecules28062764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Photoluminescent liquid-crystalline (PLLC) molecules, which can easily tune the PL behavior through the crystal (Cry)-LC phase transition, have attracted significant attention. Previously, we have demonstrated that the incorporation of a semifluoroalkoxy chain into π-conjugated mesogen is a promising approach for developing PLLC molecules with PL and SmA LC characteristics. We focused on the LC and PL characteristics of the molecules induced by the semifluoroalkoxy chain and fluorinated tolanes in the condensed phase. In this study, we developed cyano- or ethoxycarbonyl-terminated donor-π-acceptor-type fluorinated tolanes containing a semifluoroalkoxy flexible chain. The cyano-terminated fluorinated tolanes exhibited intense light-blue photoluminescence in the crystalline phase and did not exhibit any LC phase. In contrast, blue photoluminescence in the ethoxycarbonyl-terminated analogs was slightly weak; however, they exhibited Cry-SmA phase transition during the heating and cooling processes. The PL intensity of the ethoxycarbonyl-terminated fluorinated tolanes significantly decreased in the SmA phase; however, their PL colors changed during the Cry-SmA phase transition. This indicates that the developed tolanes are promising temperature-dependent PL materials, such as PL thermosensors or PL thermometers.
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Affiliation(s)
- Shigeyuki Yamada
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Keigo Yoshida
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Mitsuki Kataoka
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Mitsuo Hara
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan
| | - Tsutomu Konno
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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Łoś J, Drozd-Rzoska A, Rzoska S. Critical-like behavior of low-frequency dielectric properties in compressed liquid crystalline octyloxycyanobiphenyl (8OCB) and its nanocolloid with paraelectric BaTiO3. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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Kovalchuk O, Kovalchuk T, Tomašovičová N, Timko M, Zakutanska K, Miakota D, Kopčanský P, Shevchuk O, Garbovskiy Y. Dielectric and electrical properties of nematic liquid crystals 6CB doped with iron oxide nanoparticles. The combined effect of nanodopant concentration and cell thickness. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Łoś J, Drozd-Rzoska A, Rzoska SJ, Czupryński K. The impact of ionic contribution to dielectric permittivity in 11CB liquid crystal and its colloids with BaTiO 3 nanoparticles. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2022; 45:74. [PMID: 36074208 PMCID: PMC9458595 DOI: 10.1140/epje/s10189-022-00228-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
The report shows the temperature behavior of the real part of dielectric permittivity in the static (dielectric constant) and low-frequency (LF) domains in bulk samples of 11CB and its BaTiO3-based nanocolloids. The study covers the isotropic liquid (I), nematic (N), smectic A (SmA), and solid crystal (Cr) phases. For each phase, the dominance of pretransitional fluctuations, significantly moderated by nanoparticles, is shown. The authors consider separate focuses on the dielectric constant [Formula: see text] evolution in the static domain, yielding mainly response from permanent dipole moment and its arrangement, and in the low-frequency (LF) domain [Formula: see text] (where [Formula: see text] is for the real part of dielectric permittivity in the LF domain), which is associated solely with ionic-related polarization mechanisms. All of these led to new experimental evidence concerning I-N, N-SmA, and SmA-solid transitions, focusing on the strength and extent of pretransitional effects, critical exponents, and phase transitions discontinuities. The strong evidence for pretransitional effects near the SmA-Cr transition is notable, particularly regarding [Formula: see text]. Studies are supplemented by the discussion of DC electric conductivity-a parameter also related to the LF domain. Finally, the validity of the relation [Formula: see text] (where f stands for frequency, and A is a constant parameter), often used for discussing dielectric spectra in LC compound and its nanocolloids in the LF domain, is examined.
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Affiliation(s)
- Joanna Łoś
- Institute of High Pressure Physics, Polish Academy of Sciences, X-PressMatter Lab, ul. Sokołowska 29/37, 01-142, Warsaw, Poland.
| | - Aleksandra Drozd-Rzoska
- Institute of High Pressure Physics, Polish Academy of Sciences, X-PressMatter Lab, ul. Sokołowska 29/37, 01-142, Warsaw, Poland
| | - Sylwester J Rzoska
- Institute of High Pressure Physics, Polish Academy of Sciences, X-PressMatter Lab, ul. Sokołowska 29/37, 01-142, Warsaw, Poland
| | - Krzysztof Czupryński
- Faculty of Advanced Technologies and Chemistry, Military University of Technology, ul. gen. Sylwestra Kaliskiego 2, 00-908, Warsaw, Poland
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Salah MB, Nasri R, Alharbi AN, Althagafi TM, Soltani T. Thermotropic liquid crystal doped with ferroelectric nanoparticles: Electrical behavior and ion trapping phenomenon. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119142] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Knapkiewicz M, Robakowska M, Rachocki A. Thermal stabilization of the smectic-Ca* phase by doping with photo-active reactive mesogen. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Deptuch A, Lalik S, Jasiurkowska-Delaporte M, Juszyńska-Gałązka E, Drzewicz A, Urbańska M, Marzec M. Comparative study of electrooptic, dielectric, and structural properties of two glassforming antiferroelectric mixtures with a high tilt angle. Phys Rev E 2022; 105:024705. [PMID: 35291092 DOI: 10.1103/physreve.105.024705] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 02/06/2022] [Indexed: 06/14/2023]
Abstract
Vitrification of the antiferroelectric smectic-C_{A}^{*} phase is reported for the orthoconic mixture W-1000 and its new derivative W-356. The crystallization is not observed even upon slow cooling and the cold crystallization on subsequent heating is also absent. Molecular dynamics in the smectic phases of both mixtures is investigated down to 173 K and the fragility parameters are determined from the temperature behavior of the α-process. X-ray diffraction is applied to compare the structural parameters of W-356 and W-1000 as well as to study the structural changes during the glass transition of the Sm-C_{A}^{*} phase. The evolution of the smectic layer order within the Sm-C_{A}^{*} glass is reported, while the correlation length of the short-range order in the smectic layers is shown to be almost constant below the glass transition temperature. Electrooptic properties of W-356: spontaneous polarization, tilt angle and switching time are determined and compared with these of W-1000. The observed differences between the properties of W-356 and W-1000 might be explained by the dimer formation of components with the -C≡N terminal group, present only in the W-356 mixture, and by the different structure of the aromatic molecular core in one of the W-356 components.
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Affiliation(s)
- Aleksandra Deptuch
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, PL-31342 Kraków, Poland
| | - Sebastian Lalik
- M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, PL-30348 Kraków, Poland
| | | | - Ewa Juszyńska-Gałązka
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, PL-31342 Kraków, Poland
| | - Anna Drzewicz
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, PL-31342 Kraków, Poland
| | - Magdalena Urbańska
- Institute of Chemistry, Military University of Technology, Kaliskiego 2, PL-00908 Warsaw, Poland
| | - Monika Marzec
- M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, PL-30348 Kraków, Poland
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Modifications of FLC Physical Properties through Doping with Fe 2O 3 Nanoparticles (Part I). MATERIALS 2021; 14:ma14164722. [PMID: 34443243 PMCID: PMC8399294 DOI: 10.3390/ma14164722] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 02/05/2023]
Abstract
The aim of this paper is to show, by systematic studies, the influence of γ-Fe2O3 nanoparticles on the physical parameters of the liquid crystalline matrix, exhibiting a ferroelectric phase in a wide temperature range. The detailed research was carried out by using diffraction (PXRD), microscopic (OM, SEM, FCPM, POM), thermal (DSC), optical (TLI), electric and spectroscopic (FTIR) methods. We show that even the smallest concentration of γ-Fe2O3 nanoparticles largely modifies the parameters of the ferroelectric SmC* phase, such as spontaneous polarization, switching time, tilt angle, rotational viscosity, dispersion anchoring energy coefficient and helix pitch. The admixture also causes a significant reduction in the temperature of phase transitions, broadening the SmA* phase at the expense of the SmC* phase and strong streaking of the texture. We present and explain the non-monotonic modification of these parameters with an increase in the nanoparticle concentration. The influence of oleic acid admixture on these parameters is also widely discussed. We have shown that certain parameters of organic-metal nanocomposites can be controlled by the appropriate amount of metal admixture.
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Agrahari K, Nautiyal VK, Vimal T, Pandey S, Kumar S, Manohar R. Modification in different physical parameters of orthoconic antiferroelectric liquid crystal mixture via the dispersion of hexanethiol capped silver nanoparticles. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Urbańska M, Morawiak P, Senderek M. Investigation of the tilt angle and spontaneous polarisation of antiferroelectric liquid crystals with a chiral centre based on (S)-(+)-3-octanol. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115378] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Garbovskiy Y. Conventional and unconventional ionic phenomena in tunable soft materials made of liquid crystals and nanoparticles. NANO EXPRESS 2021. [DOI: 10.1088/2632-959x/abe652] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
A great variety of tunable multifunctional materials can be produced by combining nanoparticles and liquid crystals. Typically, the tunability of such soft nanocomposites is achieved via external electric fields resulting in the field-induced reorientation of liquid crystals. This reorientation can be altered by ions normally present in liquid crystals in small quantities. In addition, nanomaterials dispersed in liquid crystals can also affect the behavior of ions. Therefore, an understanding of ionic phenomena in liquid crystals doped with nanoparticles is essential for future advances in liquid crystal-aided nanoscience and nanotechnology. This paper provides an overview of the ionic effects observed in liquid crystals doped with nanomaterials. An introduction to liquid crystals is followed by a brief overview of nanomaterials in liquid crystals. After giving a basic description of ions in liquid crystals and experimental methods to measure them, a wide range of ionic phenomena in liquid crystals doped with different types of nanomaterials is discussed. After that, both existing and emerging applications of tunable soft materials made of liquid crystals and nanodopants are presented with an emphasis on the role of ionic effects in such systems. Finally, the discussion of unsolved problems and future research directions completes the review.
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Uttam R, Kumar S, Dhar R. Magnified charge carrier conduction, permittivity, and mesomorphic properties of columnar structure of a room temperature discotic liquid crystalline material due to the dispersion of low concentration ferroelectric nanoparticles. Phys Rev E 2020; 102:052702. [PMID: 33327178 DOI: 10.1103/physreve.102.052702] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/06/2020] [Indexed: 11/07/2022]
Abstract
Liquid crystal nanocomposites have been a hot topic of research due to optimization of physical properties with such blending. There are several reports on enhancement of physical properties of nematic liquid crystals due to the blending of the nanomaterials. L. M. Lopatina and J. V. Selinger [Phys. Rev. Lett. 102, 197802 (2009)]10.1103/PhysRevLett.102.197802 have even proposed a theory based on experimental results for the enhancement of the properties of the nematic mesophase in the presence of ferroelectric nanoparticles. However, discotic liquid crystal nanocomposites are less studied. In the present experimental work, we have studied the effect of ferroelectric (BaTiO_{3}) nanoparticles on a room temperature discotic liquid crystalline material, namely 1,5-dihydroxy-2,3,6,7-tetrakis(3,7-dimethyloctyloxy)-9,10-anthraquinone. We investigated the physical properties of low concentration ferroelectric nanoparticle dispersed discotic columnar structure, using calorimetric, optical, x-ray diffraction, and dielectric spectroscopy tools. Results show that inclusion of ferroelectric nanoparticles in the discotic matrix consolidates the stability of the columnar matrix of the Col_{h} phase by virtue of their ferroic nature. An enhancement in charge carrier conductivity by several orders of magnitude at ambient conditions has been observed which makes such systems highly appropriate for one-dimensional conductors. Low concentration of BaTiO_{3} nanoparticles substantially enhanced permittivity of the system also. A molecular relaxation mode has been observed in the middle frequency range of the dielectric spectra. Enhancement of these important parameters could be possible due to the ferroelectric nature of the dispersed nanoparticles.
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Affiliation(s)
- Rahul Uttam
- Centre of Material Sciences, University of Allahabad, Prayagraj 211002, India
| | - Sandeep Kumar
- Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bengaluru 560080, India.,Department of Chemistry, Nitte Meenakshi Institute of Technology, Bengaluru 560064, India
| | - Ravindra Dhar
- Centre of Material Sciences, University of Allahabad, Prayagraj 211002, India
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Enhanced charge carrier conduction and other characteristic parameters of hexagonal plastic columnar phase of a discotic liquid crystalline material due to functionalized gold nanoparticles. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113985] [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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