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Pisharody GR, Sahoo P, Shankar Rao DS, Ramakrishna Matte HSS, Sikdar D, Krishna Prasad S. IR regulation through preferential placement of h-BN nanosheets in a polymer network liquid crystal. MATERIALS HORIZONS 2024; 11:554-565. [PMID: 37982355 DOI: 10.1039/d3mh01467c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
Recently, there has been a great deal of interest in devices which effectively shield near-infrared light with an additional feature of external field tunability, particularly for energy-saving applications. This article demonstrates an approach for fabricating a highly efficient near-infrared regulating device based on a polymer network liquid crystal reinforced with nanosheets of hexagonal-boron nitride (BN). The device achieves ∼84% IR scattering capability over a wavelength range of 800-2300 nm, and can also be regulated by an electric field. Interestingly, the observed high IR regulation is despite individual components of the composite being IR transparent, in stark contrast to earlier attempted incorporation of IR-absorbing/scattering particles. Detailed experimental characterization methods including FESEM corroborated with EDS and Raman spectroscopy suggest that the preferential positioning of the BN nanosheets, a consequence of the photo-polymerization process, is responsible for the observed feature. The IR reflectivity/back scattering that is doubled upon incorporation of the nanosheets results in an enhanced convective/radiative heat barrier capability, as evidenced by thermal imaging and significant (2 °C) reduction in ambient temperature upon one-Sun illumination. Numerical simulation results are also found to be in good agreement with the observed enhanced reflectance values for the BN-incorporated case. The presence of BN augments the mechanical rigidity of the system by a factor of 6.8 without compromising on the device operating voltage. The protocol employed is quite general and thus advantageous with far-reaching applications in passive cooling of buildings and structures, in thermal camouflaging, and in overall energy management.
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Affiliation(s)
- Gayathri R Pisharody
- Centre for Nano and Soft Matter Sciences, Arkavathi, Survey No. 7, Shivanapura, Dasanapura Hobli, Bengaluru 562162, India.
- Manipal Academy of Higher Education (MAHE), Manipal, 576104, India
| | - Priyabrata Sahoo
- Centre for Nano and Soft Matter Sciences, Arkavathi, Survey No. 7, Shivanapura, Dasanapura Hobli, Bengaluru 562162, India.
- Manipal Academy of Higher Education (MAHE), Manipal, 576104, India
| | - D S Shankar Rao
- Centre for Nano and Soft Matter Sciences, Arkavathi, Survey No. 7, Shivanapura, Dasanapura Hobli, Bengaluru 562162, India.
| | - H S S Ramakrishna Matte
- Centre for Nano and Soft Matter Sciences, Arkavathi, Survey No. 7, Shivanapura, Dasanapura Hobli, Bengaluru 562162, India.
| | - Debabrata Sikdar
- Department of Electronics and Electrical Engineering, Indian Institute of Technology Guwahati, Assam, 781039, India
| | - S Krishna Prasad
- Centre for Nano and Soft Matter Sciences, Arkavathi, Survey No. 7, Shivanapura, Dasanapura Hobli, Bengaluru 562162, India.
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Anu, Varshney D, Yadav K, Prakash J, Meena H, Singh G. Tunable dielectric and memory features of ferroelectric layered perovskite Bi4Ti3O12 nanoparticles doped nematic liquid crystal composite. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kumari A, Dhawan S, Singh H, Haridas V, Sinha A. Pseudopeptidic polymers for modulating electro-optic switching, dielectric and electrical properties of liquid crystal. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Zhang H, Liu J, Gao S, Li F, Ma C, Miao Z, Shen W. Preparation of transmittance-switchable composites from a coexistent system of polymer-dispersed and polymer-stabilized cholesteric liquid crystals. Phys Chem Chem Phys 2022; 24:18703-18712. [PMID: 35899743 DOI: 10.1039/d2cp01963a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polymer-dispersed and polymer-stabilized liquid crystals (PD&PSLCs) are the coexistent systems of PDLCs and PSLCs, in which a mesogenic polymer network forms in the LC droplets to construct the PSLC system and the combination of the LC domains and the isotropic polymer matrix makes up the PDLC system. In this work, a PD&PS cholesteric LC (PD&PSCLC) system, where the isotropic polymer walls make up the PDCLC microstructure and the liquid crystalline polymer network in the CLC droplets constructs the PSCLC system, is fabricated successfully. The CLCs are composed of a negative dielectric anisotropy nematic LC and a chiral dopant. Owing to the stabilizing effect of the liquid crystalline polymer network, the planar texture of the CLCs can be retained after the preparation process, and the PD&PSCLC sample is in a large-transmittance state. The action of a low-frequency electric field induces the disordered texture of the CLCs and the light-scattering (low-transmittance) state because of the electro-hydrodynamic effect and dynamic scattering effects. After the removal of the low-frequency electric field, the stabilizing effect of the liquid crystalline polymer network induces the CLC molecules to return to the homogeneous orientation state, and the sample also re-obtains the large transmittance. This work may provide a facile approach to fabricating polymer/CLC composites with switchable transmittance for reverse-mode smart windows.
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Affiliation(s)
- Huimin Zhang
- Xi'an Key Laboratory of Advanced Photo-electronics Materials and Energy Conversion Device, School of Electronic Information, Xijing University, Xi'an 710123, P. R. China
| | - Jie Liu
- Xi'an Key Laboratory of Advanced Photo-electronics Materials and Energy Conversion Device, School of Electronic Information, Xijing University, Xi'an 710123, P. R. China
| | - Shiyan Gao
- Xi'an Key Laboratory of Advanced Photo-electronics Materials and Energy Conversion Device, School of Electronic Information, Xijing University, Xi'an 710123, P. R. China
| | - Fei Li
- Xi'an Manareco New Materials Co Ltd, Xi'an 710077, P. R. China
| | - Cheng Ma
- Xi'an Key Laboratory of Advanced Photo-electronics Materials and Energy Conversion Device, School of Electronic Information, Xijing University, Xi'an 710123, P. R. China
| | - Zongcheng Miao
- School of Artificial Intelligence, Optics and Electronics (iOPEN), Northwestern Polytechnical University, Xi'an 710072, Shaanxi, P. R. China.
| | - Wenbo Shen
- Research Center for Humanoid Sensing, Zhejiang Laboratory, Hangzhou, 311121, P. R. China.
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Enhanced electrochemical and electro-optical properties of nematic liquid crystal doped with Ni:ZnCdS/ZnS core/shell quantum dots. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114373] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Eskalen H, Uruş S, Özgan Ş. Microwave-Assisted Synthesis of Mushrooms Like MWCNT/SiO2@ZnO Nanocomposite: Influence on Nematic Liquid Crystal E7 and Highly Effective Photocatalytic Activity in Degradation of Methyl Blue. J Inorg Organomet Polym Mater 2020. [DOI: 10.1007/s10904-020-01804-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Li X, Guo Y, Huai H, Yang Y, Sun Y, Zhang C, Sun Y. The effect of monomer and chiral dopant content on reverse-mode polymer stabilized cholesteric liquid crystal display. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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