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Raczyńska V, Górny K, Raczyński P, Dendzik Z, Starzonek S. Two-dimensional phases of confined 5-cyano-biphenyl: Computer simulation study. Phys Rev E 2023; 108:034702. [PMID: 37849085 DOI: 10.1103/physreve.108.034702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 08/25/2023] [Indexed: 10/19/2023]
Abstract
The properties of composites of mesogens and two-dimensional (2D) materials are of great interest due to their practical applications in flexible displays, optoelectronics, microelectronics, and novel nanodevices. The properties of such composites are very complex and strongly depend on the interactions between the host material and the mesogen filling. We have performed molecular dynamics simulations for 4-cyano-4^{'}-pentylbiphenyl embedded between graphene and hexagonal 2D boron nitride layers. The structural and dynamical properties of such systems were investigated in terms of the order parameters, density profiles, mean square displacement, and autocorrelation function of the single-molecule dipole moment. Our simulations have shown that the mesogenic molecules form highly stable ordered layered structures and that their dynamics are strongly related to the structural properties. We have investigated not only the effects of the polarization of the host material, but also the effects of the spatial repetition of such composites by using two models of mesogens embedded in 2D layers: the direct sheet and the structure formed by multiplying a single unit of the composite in the direction perpendicular to the substrate surface.
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Affiliation(s)
- Violetta Raczyńska
- Faculty of Science and Technology, University of Silesia in Katowice, ul. 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland
| | - Krzysztof Górny
- Faculty of Science and Technology, University of Silesia in Katowice, ul. 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland
| | - Przemysław Raczyński
- Faculty of Science and Technology, University of Silesia in Katowice, ul. 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland
| | - Zbigniew Dendzik
- Faculty of Science and Technology, University of Silesia in Katowice, ul. 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland
| | - Szymon Starzonek
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, 1000 Ljubljana, Slovenia
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Ostovari F, Dehghani Z. Influence of aminated graphene nanosheets on electro–optical performance and nonlinear optical properties of nematic liquid crystal. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Bharath Kumar M, Awwal Adeshina M, Kang D, Jee Y, Kim T, Choi M, Park J. Enhancement of Birefringence in Reduced Graphene Oxide Doped Liquid Crystal. NANOMATERIALS 2020; 10:nano10050842. [PMID: 32353931 PMCID: PMC7712246 DOI: 10.3390/nano10050842] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/16/2020] [Accepted: 04/26/2020] [Indexed: 11/16/2022]
Abstract
We investigated the effect of reduced graphene oxide (rGO) doping on the birefringence of 5CB liquid crystal (LC). The characteristics of the synthesized rGO and LC-rGO composite with different rGO concentrations were analyzed by atomic force microscopy, X-ray photoelectron spectroscopy, white light polarized microscopy, voltage-dependent transmission measurement, and differential scanning calorimetry. We found that doping LC with an appropriate concentration of rGO enhances the birefringence of the LC. This is mainly due to the improved anisotropy of polarizability, which stems from the high shape anisotropy of rGO. However, the aggregation of rGO reduces the birefringence by decreasing the anisotropy of polarizability as well as the order parameter. Our study shows the promising potential of LC-rGO for developing various electro-optic devices that offer improved electro-optic effects.
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Affiliation(s)
- Mareddi Bharath Kumar
- Department of Electrical Engineering, Kyungpook National University, Daegu 41566, Korea; (M.B.K.); (M.A.A.); (D.K.)
| | - Mohammad Awwal Adeshina
- Department of Electrical Engineering, Kyungpook National University, Daegu 41566, Korea; (M.B.K.); (M.A.A.); (D.K.)
| | - Daekyung Kang
- Department of Electrical Engineering, Kyungpook National University, Daegu 41566, Korea; (M.B.K.); (M.A.A.); (D.K.)
| | - Youngho Jee
- Department Chemistry, Kyungpook National University, Daegu 41566, Korea;
- Cresin Co., Ltd., Gyeongsangbuk-do 40040, Korea
| | - Taewan Kim
- Department of Electrical Engineering and Smart Grid Research Center, Jeonbuk National University, Jeonju 54896, Korea;
| | - Muhan Choi
- School of Electronics Engineering, Kyungpook National University, Daegu 41566, Korea;
| | - Jonghoo Park
- Department of Electrical Engineering, Kyungpook National University, Daegu 41566, Korea; (M.B.K.); (M.A.A.); (D.K.)
- Correspondence:
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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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Górny K, Raczyńska V, Raczyński P, Dendzik Z, Starzonek S. Impact of polarized nanotube surface on ultrathin mesogen film properties: Computer simulation study. Phys Rev E 2019; 99:022701. [PMID: 30934350 DOI: 10.1103/physreve.99.022701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Indexed: 11/07/2022]
Abstract
We studied properties of monolayer films of n-cyanobiphenyl (with n=5,...,8) series of mesogens anchored on the surface of single walled boron nitride nanotube. In order to assess the impact of substrate polarization on the ordering effects we compare translational and reorientational dynamics of the films with the characteristics of analogous carbon and silicon carbide nanotube based systems. We observed significant increase of the ordering degree accompanied by increased thermal stability. This ordering is less selective than those induced by the silicon carbide nanotube, which were previously reported. The antiparallel orientation of the nearest neighboring mesogens is predominant, while the system does not exhibit any long-range spatial correlations which indicates that the size of the domains is constrained to this region. These features might be of potential importance in the design of novel optoelectronic devices.
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Affiliation(s)
- Krzysztof Górny
- Institute of Physics, University of Silesia, Chorzów, Poland and Silesian Centre of Education and Interdisciplinary Research, 75 Pułku Piechoty 1a, 41-500 Chorzów, Poland
| | - Violetta Raczyńska
- Institute of Physics, University of Silesia, Chorzów, Poland and Silesian Centre of Education and Interdisciplinary Research, 75 Pułku Piechoty 1a, 41-500 Chorzów, Poland
| | - Przemysław Raczyński
- Institute of Physics, University of Silesia, Chorzów, Poland and Silesian Centre of Education and Interdisciplinary Research, 75 Pułku Piechoty 1a, 41-500 Chorzów, Poland
| | - Zbigniew Dendzik
- Institute of Physics, University of Silesia, Chorzów, Poland and Silesian Centre of Education and Interdisciplinary Research, 75 Pułku Piechoty 1a, 41-500 Chorzów, Poland
| | - Szymon Starzonek
- Institute of High Pressure Physics, Polish Academy of Sciences, Sokołowska 29/37, 01-142 Warsaw, Poland
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Evolution of electro-chemical and electro-optical properties of nematic liquid crystal doped with graphene oxide. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.05.138] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Zhang S, Pelligra CI, Feng X, Osuji CO. Directed Assembly of Hybrid Nanomaterials and Nanocomposites. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1705794. [PMID: 29520839 DOI: 10.1002/adma.201705794] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/22/2017] [Indexed: 05/19/2023]
Abstract
Hybrid nanomaterials are molecular or colloidal-level combinations of organic and inorganic materials, or otherwise strongly dissimilar materials. They are often, though not exclusively, anisotropic in shape. A canonical example is an inorganic nanorod or nanosheet sheathed in, or decorated by, a polymeric or other organic material, where both the inorganic and organic components are important for the properties of the system. Hybrid nanomaterials and nanocomposites have generated strong interest for a broad range of applications due to their functional properties. Generating macroscopic assemblies of hybrid nanomaterials and nanomaterials in nanocomposites with controlled orientation and placement by directed assembly is important for realizing such applications. Here, a survey of critical issues and themes in directed assembly of hybrid nanomaterials and nanocomposites is provided, highlighting recent efforts in this field with particular emphasis on scalable methods.
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Affiliation(s)
- Shanju Zhang
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, CA, 93407, USA
| | - Candice I Pelligra
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, 06511, USA
| | - Xunda Feng
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, 06511, USA
| | - Chinedum O Osuji
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, 06511, USA
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Basu R. Enhancement of polar anchoring strength in a graphene-nematic suspension and its effect on nematic electro-optic switching. Phys Rev E 2018; 96:012707. [PMID: 29347260 DOI: 10.1103/physreve.96.012707] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Indexed: 11/07/2022]
Abstract
A small quantity of monolayer graphene flakes is doped in a nematic liquid crystal (LC), and the effective polar anchoring strength coefficient between the LC and the alignment substrate is found to increase by an order of magnitude. The hexagonal pattern of graphene can interact with the LC's benzene rings via π-π electron stacking, enabling the LC to anchor to the graphene surface homogeneously (i.e., planar anchoring). When the LC cell is filled with the graphene-doped LC, some graphene flakes are preferentially attached to the alignment layer and modify the substrate's anchoring property. These spontaneously deposited graphene flakes promote planar anchoring at the substrate and the polar anchoring energy at alignment layer is enhanced significantly. The enhanced anchoring energy is found to impact favorably on the electro-optic response of the LC. Additional studies reveal that the nematic electro-optic switching is significantly faster in the LC-graphene hybrid than that of the pure LC.
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Affiliation(s)
- Rajratan Basu
- Department of Physics, Soft Matter and Nanomaterials Laboratory, The United States Naval Academy, Annapolis, Maryland 21402, USA
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Lin P, Cong Y, Sun C, Zhang B. Non-covalent modification of reduced graphene oxide by a chiral liquid crystalline surfactant. NANOSCALE 2016; 8:2403-2411. [PMID: 26754831 DOI: 10.1039/c5nr07620j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In order to effectively disperse reduced graphene oxide (RGO) in functional materials and take full advantage of its exceptional physical and chemical properties, a novel and effective approach for non-covalent modification of RGO by a chiral liquid crystalline surfactant (CLCS) consisting of chiral mesogenic units, nematic mesogenic units with carboxyl groups and non-mesogenic units with a polycyclic conjugated structure is firstly established. The polycyclic conjugated structure can anchor onto the RGO surface via π-π interactions, the chiral mesogenic units possess affinity for chiral materials by joining the helical matrix of chiral material and the carboxyl groups in nematic mesogenic units are supposed to form coordination bonds with nano zinc oxide (ZnO) to fabricate functional nano hybrids. The transmittances of CLCS-RGO hybrids exhibit S-shaped nonlinear increase with the increase of wavelength, but the total transmittances from 220 nm to 800 nm show a linear decreasing trend with the increase of RGO content in the CLCS-RGO hybrid. Due to the superior thermal properties of RGO and the interactions between RGO and CLCS, the dispersed RGO can improve the glass transition and increase the thermal stability and decomposition activation energy of CLCS. The intercalation of RGO can decrease the thermochromism temperature and improve the pitch uniformity of CLCS. Furthermore, CLCS can promote the dispersion of RGO in chiral nematic liquid crystals (CNLCs), and the CNLC-RGO-CLCS hybrids present decreased driving voltage and accelerated electro-optical response. The CLCS non-covalently modified RGO can strengthen the photocatalytic degradation of ZnO by suppressing the aggregation of ZnO and RGO.
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Affiliation(s)
- Pengcheng Lin
- Center for Molecular Science and Engineering, Northeastern University, 3 Wenhua Road, Shenyang 110819, P. R. China.
| | - Yuehua Cong
- Center for Molecular Science and Engineering, Northeastern University, 3 Wenhua Road, Shenyang 110819, P. R. China.
| | - Cong Sun
- Center for Molecular Science and Engineering, Northeastern University, 3 Wenhua Road, Shenyang 110819, P. R. China.
| | - Baoyan Zhang
- Center for Molecular Science and Engineering, Northeastern University, 3 Wenhua Road, Shenyang 110819, P. R. China.
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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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