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Singh PK, Dhar R, Dabrowski R. Enhancement of dielectric and electro-optical characteristics of liquid crystalline material 4'-octyl-4-cyano-biphenyl with dispersed functionalized and nonfunctionalized multiwalled carbon nanotubes. Phys Rev E 2023; 107:044704. [PMID: 37198864 DOI: 10.1103/physreve.107.044704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 03/01/2023] [Indexed: 05/19/2023]
Abstract
For recent applications, liquid crystal-carbon nanotube based nanocomposite systems have been proven to be highly attractive. In this paper, we give a thorough analysis of a nanocomposite system made of both functionalized and nonfunctionalized multiwalled carbon nanotubes that are disseminated in a 4'-octyl-4-cyano-biphenyl liquid crystal medium. Thermodynamic study reveals a decrease in the nanocomposites' transition temperatures. In contrast to nonfunctionalized multiwalled carbon nanotube dispersed systems, the enthalpy of functionalized multiwalled carbon nanotube dispersed systems has increased. In comparison to the pure sample, the dispersed nanocomposites have a smaller optical band gap. A rise in the longitudinal component of permittivity and, consequently, the dielectric anisotropy of the dispersed nanocomposites has been observed by dielectric studies. When compared to the pure sample, the conductivity of both dispersed nanocomposite materials has increased by two orders of magnitude. For the system with dispersed functionalized multiwalled carbon nanotubes, the threshold voltage, splay elastic constant, and rotational viscosity all decreased. For the dispersed nanocomposite of nonfunctionalized multiwalled carbon nanotubes, the value of the threshold voltage is somewhat decreased but the rotational viscosity and splay elastic constant both are enhanced. These findings show the applicability of the liquid crystal nanocomposites for display and electro-optical systems with appropriate tuning of the parameters.
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Affiliation(s)
- Praveen Kumar Singh
- Centre of Material Sciences, University of Allahabad, Prayagraj-211002, India
| | - Ravindra Dhar
- Centre of Material Sciences, University of Allahabad, Prayagraj-211002, India
| | - Roman Dabrowski
- Institute of Applied Sciences and Chemistry, Military University of Technology, Warsaw 00-908, Poland
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Draude AP, Dierking I. Thermotropic liquid crystals with low-dimensional carbon allotropes. NANO EXPRESS 2021. [DOI: 10.1088/2632-959x/abdf2d] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Abstract
As display devices based on liquid crystals have matured over the last decades, liquid crystal research has shifted its priorities in slightly different directions, such as sensors, photonics, nanotechnology and even more biologically related fields like drug delivery. This implied a change of emphasis in the development of novel materials, of which a completely new class of liquid crystal based composites emerged, that of nanoparticle-dispersed liquid crystals. The underlying ideas were to add functionality, while maintaining switchability, and the exploitation of liquid crystal self-organisation to build hierarchical nanostructures. Of particular interest for applications are dispersions of carbon nanomaterials, such as fullerenes, nanotubes and the graphene variants, due to their interactions with conventional liquid crystals. While such systems have been investigated for the past two decades, we concentrate in this review on the effects of dimensionality of the dispersed carbon nanoparticles, which goes hand in hand with the more recent developments in this field. Examples are the doping of 0D fullerenes in liquid crystals and implications for Blue Phase stability, or 1D nanotubes in nematic and ferroelectric liquid crystals, questions of dispersibility and applications as alignment media in ITO-free devices. Graphene (2D) and especially graphene oxide are mainly investigated for their formation of lyotropic liquid crystals. We here discuss the more recent aspects of dispersion in thermotropics.
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Samoilov A, Minenko S, Sushynskyi O, Lisetski L, Lebovka N. Optical and calorimetric studies of quercetin-doped liquid crystals: Effects of molecular aggregation. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111689] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Perspectives in Liquid-Crystal-Aided Nanotechnology and Nanoscience. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9122512] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The research field of liquid crystals and their applications is recently changing from being largely focused on display applications and optical shutter elements in various fields, to quite novel and diverse applications in the area of nanotechnology and nanoscience. Functional nanoparticles have recently been used to a significant extent to modify the physical properties of liquid crystals by the addition of ferroelectric and magnetic particles of different shapes, such as arbitrary and spherical, rods, wires and discs. Also, particles influencing optical properties are increasingly popular, such as quantum dots, plasmonic, semiconductors and metamaterials. The self-organization of liquid crystals is exploited to order templates and orient nanoparticles. Similarly, nanoparticles such as rods, nanotubes and graphene oxide are shown to form lyotropic liquid crystal phases in the presence of isotropic host solvents. These effects lead to a wealth of novel applications, many of which will be reviewed in this publication.
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Chang C, Zhao Y, Liu Y, An L. Liquid crystallinity of carbon nanotubes. RSC Adv 2018; 8:15780-15795. [PMID: 35539493 PMCID: PMC9080064 DOI: 10.1039/c8ra00879e] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/12/2018] [Indexed: 01/30/2023] Open
Abstract
In this review, we first briefly recapitulate the orientation characteristics of liquid crystalline carbon nanotubes (CNTs), emphasizing their inherent properties. Both the high Young's modulus and the strong attractive interaction between them make the liquid crystallinity apt to show splay deformations (splay defects). It is these defects that often produce apparent low-order structures for long and deformed nanotubes. However, the application of doping, shearing, magnetic or electric fields will be efficient routes toward highly ordered CNT assemblies from such defects. Then, we describe the electrical behavior of CNTs in the electric field, which combines desirable features of the CNTS with those of classical liquid crystals (LCs). An electric field will generate an induced dipole moment on CNTs and align them in the field direction, minimizing the dipolar energy. Finally, we review the potential application of CNTs in the area of liquid crystal displays (LCD). In the LC cell unit, CNTs as dopants in LC layers can have compatible stability with LCs, with the orientation consistent and with surprising complementary advantages. And also CNT films as nanostructured electrodes can substitute ITO electrodes in the LC cell unit, exhibiting a strong electrical anisotropy due to their excellent axial conductivity. Furthermore, CNT films as an alignment layer have the potential to replace the traditional PI film, aligning LC molecules effectively along the direction of the nanotubes. Besides, CNTs acting as polarizers can absorb or transmit incident light when the electric vector propagates parallel or perpendicular to the nanotube axis. All of these applications demonstrate that CNTs in LC ordering will effectively improve the performance of materials and their related devices. Thus, we should improve the ordering of CNT assemblies as far as possible, which is critical to make full use of their exceptional axial properties and further to develop novel materials and applications successfully.
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Affiliation(s)
- Chunrui Chang
- North China University of Science and Technology, College of Science Tangshan 063009 China +86 18032513036
| | - Ying Zhao
- Hebei Milestone Electronic Material Limited Company, Research and Development Department of Liquid Crystal Mixture Shijiazhuang 050600 China
| | - Ying Liu
- North China University of Science and Technology, College of Science Tangshan 063009 China +86 18032513036
| | - Libao An
- North China University of Science and Technology, College of Mechanical Engineering Tangshan 063009 China
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Krishna Prasad S, Baral M, Murali A, Jaisankar SN. Carbon Nanotube Reinforced Polymer-Stabilized Liquid Crystal Device: Lowered and Thermally Invariant Threshold with Accelerated Dynamics. ACS APPLIED MATERIALS & INTERFACES 2017; 9:26622-26629. [PMID: 28727450 DOI: 10.1021/acsami.7b08825] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Polymer-stabilized liquid crystal (PSLC) devices comprise a polymer matrix in an otherwise continuous phase of liquid crystal. The fibrils of the polymer provide, even in the bulk, virtual surfaces with finite anchoring energy resulting in attractive electro-optic properties. Here, we describe a novel variation of the PSLC device fabricated by reinforcing the polymer matrix with polymer-capped single-walled carbon nanotubes (CNTs). The most important outcome of this strengthening of the polymer strands is that the threshold voltage associated with the electro-optic switching becomes essentially temperature independent in marked contrast to the significant thermal variation seen in the absence of the nanotubes. The reinforcement reduces the magnitude of the threshold voltage, and notably accelerates the switching dynamics and the effective splay elasticity. Each of these attributes is quite attractive from the device operation point of view, especially the circuit design of the required drivers. The amelioration is caused by the polymer decorating CNTs being structurally identical to that of the matrix. The resulting good compatibility between CNTs and the matrix prevents the CNTs from drifting away from the matrix polymer, a lacuna in previous attempts to have CNTs in PSLC systems. The difference in the morphology, perhaps the primary cause for the effects seen, is noted in the electron microscopy images of the films.
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Affiliation(s)
- S Krishna Prasad
- Centre for Nano and Soft Matter Sciences , Jalahalli, Bengaluru 560 013, India
| | - Marlin Baral
- Centre for Nano and Soft Matter Sciences , Jalahalli, Bengaluru 560 013, India
| | - Adhigan Murali
- Polymer Science & Technology Division, Council of Scientific and Industrial Research (CSIR)-Central Leather Research Institute (CLRI) , Adyar, Chennai 600 020, India
| | - Sellamuthu N Jaisankar
- Polymer Science & Technology Division, Council of Scientific and Industrial Research (CSIR)-Central Leather Research Institute (CLRI) , Adyar, Chennai 600 020, India
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Bale S, Liyana-Arachchi TP, Hung FR. Molecular dynamics simulation of single-walled carbon nanotubes inside liquid crystals. MOLECULAR SIMULATION 2016. [DOI: 10.1080/08927022.2016.1174859] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Shivkumar Bale
- Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, USA
| | - Thilanga P. Liyana-Arachchi
- Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, USA
- Department of Chemistry, University of Florida, Gainesville, FL, USA
| | - Francisco R. Hung
- Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, USA
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García-García A, Vergaz R, Algorri JF, Zito G, Cacace T, Marino A, Otón JM, Geday MA. Reorientation of single-wall carbon nanotubes in negative anisotropy liquid crystals by an electric field. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:825-33. [PMID: 27547599 PMCID: PMC4979768 DOI: 10.3762/bjnano.7.74] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 05/12/2016] [Indexed: 05/02/2023]
Abstract
Single-wall carbon nanotubes (SWCNT) are anisotropic nanoparticles that can cause modifications in the electrical and electro-optical properties of liquid crystals. The control of the SWCNT concentration, distribution and reorientation in such self-organized fluids allows for the possibility of tuning the liquid crystal properties. The alignment and reorientation of CNTs are studied in a system where the liquid crystal orientation effect has been isolated. Complementary studies including Raman spectroscopy, microscopic inspection and impedance studies were carried out. The results reveal an ordered reorientation of the CNTs induced by an electric field, which does not alter the orientation of the liquid crystal molecules. Moreover, impedance spectroscopy suggests a nonnegligible anchoring force between the CNTs and the liquid crystal molecules.
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Affiliation(s)
- Amanda García-García
- CEMDATIC, E.T.S.I. Telecomunicación, Universidad Politécnica de Madrid, Avda. Complutense 30, 28040 Madrid, Spain
| | - Ricardo Vergaz
- GDAF-UC3M, Departamento de Tecnología Electrónica, Universidad Carlos III de Madrid, Butarque 15, Leganés, 28911, Spain
| | - José F Algorri
- GDAF-UC3M, Departamento de Tecnología Electrónica, Universidad Carlos III de Madrid, Butarque 15, Leganés, 28911, Spain
| | - Gianluigi Zito
- CNR-ISASI and Physics Department, University of Naples Federico II, Via Cinthia Monte S. Angelo, 80126, Naples, Italy
| | - Teresa Cacace
- CNR-ISASI and Physics Department, University of Naples Federico II, Via Cinthia Monte S. Angelo, 80126, Naples, Italy
| | - Antigone Marino
- CNR-ISASI and Physics Department, University of Naples Federico II, Via Cinthia Monte S. Angelo, 80126, Naples, Italy
| | - José M Otón
- CEMDATIC, E.T.S.I. Telecomunicación, Universidad Politécnica de Madrid, Avda. Complutense 30, 28040 Madrid, Spain
| | - Morten A Geday
- CEMDATIC, E.T.S.I. Telecomunicación, Universidad Politécnica de Madrid, Avda. Complutense 30, 28040 Madrid, Spain
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Popa-Nita V. The phase behavior of rigid rods in an anisotropic mean field with applications to carbon nanotubes in nematic liquid crystals. J Chem Phys 2015; 143:094901. [PMID: 26342384 DOI: 10.1063/1.4928655] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The phenomenological model [van der Schoot et al., J. Phys. Chem. B 112, 4512 (2008)] for predicting the alignment of carbon nanotube (CNT) dispersions in thermotropic liquid crystals is extended to include the attractive interactions between CNTs. The influence of the attractive forces (described by a spatially uniform mean field) on the phase behavior and orientational properties of the mixture are analyzed.
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Affiliation(s)
- V Popa-Nita
- Faculty of Physics, University of Bucharest, P.O. Box MG-11, Bucharest 077125, Romania
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Wang X, Cao H, Zhang L, Zhang R, Wang D, Yang Z, He W, Cao H, Yang H. Graphene Oxide Modified with Mesogenic Groups and Its Effect in Broad-Band Reflectors. Chempluschem 2015; 80:673-678. [DOI: 10.1002/cplu.201402315] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Indexed: 01/22/2023]
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García-García A, Vergaz R, Algorri JF, Quintana X, Otón JM. Electrical response of liquid crystal cells doped with multi-walled carbon nanotubes. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2015; 6:396-403. [PMID: 25821679 PMCID: PMC4362506 DOI: 10.3762/bjnano.6.39] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 01/12/2015] [Indexed: 05/02/2023]
Abstract
The inclusion of nanoparticles modifies a number of fundamental properties of many materials. Doping of nanoparticles in self-organized materials such as liquid crystals may be of interest for the reciprocal interaction between the matrix and the nanoparticles. Elongated nanoparticles and nanotubes can be aligned and reoriented by the liquid crystal, inducing noticeable changes in their optical and electrical properties. In this work, cells of liquid crystal doped with high aspect ratio multi-walled carbon nanotubes have been prepared, and their characteristic impedance has been studied at different frequencies and excitation voltages. The results demonstrate alterations in the anisotropic conductivity of the samples with the applied electric field, which can be followed by monitoring the impedance evolution with the excitation voltage. Results are consistent with a possible electric contact between the coated substrates of the LC cell caused by the reorientation of the nanotubes. The reversibility of the doped system upon removal of the electric field is quite low.
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Affiliation(s)
- Amanda García-García
- CEMDATIC, E.T.S.I. Telecomunicación, Universidad Politécnica de Madrid, Avda. Complutense 30, Madrid, E28040, Spain
| | - Ricardo Vergaz
- GDAF-UC3M, Departamento de Tecnología Electrónica, Universidad Carlos III de Madrid, Butarque 15, Leganés, E28911, Spain
| | - José Francisco Algorri
- GDAF-UC3M, Departamento de Tecnología Electrónica, Universidad Carlos III de Madrid, Butarque 15, Leganés, E28911, Spain
| | - Xabier Quintana
- CEMDATIC, E.T.S.I. Telecomunicación, Universidad Politécnica de Madrid, Avda. Complutense 30, Madrid, E28040, Spain
| | - José Manuel Otón
- CEMDATIC, E.T.S.I. Telecomunicación, Universidad Politécnica de Madrid, Avda. Complutense 30, Madrid, E28040, Spain
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Abstract
The phenomenological model to describe the liquid crystal-carbon nanotubes mixture presented in a previous paper [P. van der Schoot, V. Popa-Nita, and S. Kralj, J. Phys. Chem. B 112, 4512 (2008)] has been extended to include the isotropic carbon nanotubes-nematic thermotropic liquid crystal interaction. It is assumed that the carbon nanotubes in the isotropic phase act as an external random field on liquid crystal component. The influence of the randomly orientational disorder on the phase diagram of the mixture and orientational order parameters profiles of both components is theoretically analyzed for different values of temperature, volume fraction of carbon nanotubes, nematic carbon nanotubes-nematic liquid crystal coupling strength and the random field strength.
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Affiliation(s)
- V Popa-Nita
- Faculty of Physics, University of Bucharest, P. O. Box MG-11, Bucharest 077125, Romania
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13
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Impact of graphene incorporation on the orientational order of graphene/liquid crystal composites. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2013.11.044] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Klein S, Raynes P, Sambles R. New frontiers in anisotropic fluid-particle composites. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2013; 371:20120510. [PMID: 23459969 PMCID: PMC3638374 DOI: 10.1098/rsta.2012.0510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Affiliation(s)
- Susanne Klein
- HP Laboratories, Long Down Avenue, Stoke Gifford, Bristol BS34 8QZ, UK.
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