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Kumari A, Singh H, Dhawan S, Bhardwaj SK, Haridas V, Sinha A. Liquid crystal droplet design by using pseudopeptidic bottlebrush polymer additives. SOFT MATTER 2022; 18:7838-7849. [PMID: 36200443 DOI: 10.1039/d2sm00953f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Liquid crystal (LC) droplets are promising candidates for sensing applications due to their high sensitivity to surface anchoring changes, resulting in readily detectable optical effects. Herein, we have designed and synthesized amino acid-based bottlebrush polymers and investigated their impact on LC director configurations in the droplets. The pseudopeptidic bottlebrush polymers with an aromatic (phenyl) and aliphatic appendages are synthesized using ring-opening metathesis polymerization (ROMP). Polymer dispersed liquid crystal (PDLC) samples are prepared by employing pseudopeptidic bottlebrush polymers and 4-cyano-4'-pentylbiphenyl (5CB) LC via solvent-induced phase separation (SIPS) technique. Due to π-π stacking, the phenyl group favours radial configuration, whereas the repulsion between 5CB and aliphatic groups induces molecular alignment leading to bipolar droplet arrangement. The impact of various pendant groups attached to the polymer on the prepared PDLC sample's surface characteristics and free energy components is illustrated. The sensing capability of 5CB dispersed in pseudopeptidic bottlebrush polymers for various pH solutions is investigated using polarizing optical microscopy (POM). The PDLC samples are moderately permeable to water and sensitive to different pH solutions. The results demonstrate a simplified and straightforward approach for preparing LC-based biosensors and chemical sensors.
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Affiliation(s)
- Asha Kumari
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
| | - Hanuman Singh
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
| | - Sameer Dhawan
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
| | - Surya Kant Bhardwaj
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
| | - V Haridas
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
| | - Aloka Sinha
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
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Freedericksz Transitions in Twisted Ferronematics Subjected to Magnetic and Laser Field. CRYSTALS 2020. [DOI: 10.3390/cryst10070567] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The influence of the anchoring forces on the Freedericksz transition in twisted ferronematics simultaneously subjected to magnetic and laser fields is studied in this work. Using the elastic continuum theory and Gouchen model for molecular anchoring on the cell support plates, the critical field and the saturation field were calculated as a function of the laser intensity and anchoring strength for two types of ferronematics based on 5CB and CCN-37 liquid crystals.
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Cirtoaje C, Petrescu E. The Influence of Single-Walled Carbon Nanotubes on the Dynamic Properties of Nematic Liquid Crystals in Magnetic Field. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E4031. [PMID: 31817251 PMCID: PMC6947598 DOI: 10.3390/ma12244031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 11/27/2019] [Accepted: 11/29/2019] [Indexed: 11/23/2022]
Abstract
This article aims to study the impact of carbon nanotube dispersions in liquid crystals. A theoretical model for the system's dynamics is presented, considering the elastic continuum theory and a planar alignment of liquid crystal molecules on the nanotube's surface. Experimental calculation of the relaxation times in the magnetic field was made for two cases: when the field was switched on (τon), and when it was switched off (τoff). The results indicate an increase of the relaxation time by about 25% when the magnetic field was switched off, and a smaller increase (about 10%) when the field was switched on, where both were in good agreement with the theoretical values.
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Affiliation(s)
| | - Emil Petrescu
- Department of Physics, Faculty of Applied Science, University Politehnica of Bucharest, Bucharest RO-060042, Romania;
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Tiwari SP, Steckel JA, Sarma M, Bryant J, Lippert CA, Widger LR, Thompson J, Liu K, Siefert N, Hopkinson D, Shi W. Foaming Dependence on the Interface Affinities of Surfactant-like Molecules. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b03105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Surya Prakash Tiwari
- National Energy Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236, United States
- Leidos Research Support Team, 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236, United States
| | - Janice A. Steckel
- National Energy Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236, United States
| | - Moushumi Sarma
- Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40511, United States
| | - Jonathan Bryant
- Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40511, United States
| | - Cameron A. Lippert
- Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40511, United States
| | - Leland R. Widger
- Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40511, United States
| | - Jesse Thompson
- Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40511, United States
| | - Kunlei Liu
- Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40511, United States
| | - Nicholas Siefert
- National Energy Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236, United States
| | - David Hopkinson
- National Energy Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236, United States
| | - Wei Shi
- National Energy Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236, United States
- Leidos Research Support Team, 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236, United States
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Berghe G, Kline S, Burket S, Bivens L, Johnson D, Singh R. Effect of CO2 and H2O on the behavior of shale gas confined inside calcite [104] slit-like nanopore: a molecular dynamics simulation study. J Mol Model 2019; 25:293. [DOI: 10.1007/s00894-019-4180-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 08/20/2019] [Indexed: 11/24/2022]
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Affiliation(s)
- Michael P. Allen
- Department of Physics, University of Warwick, Coventry, UK
- H. H. Wills Physics Laboratory, Royal Fort, Bristol, UK
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Brasili J, Fox K, Badamo D, Berghe G, Khanal R, Singh R. Molecular dynamics simulation of shale gas confined inside slit-like calcite [104] nanopore. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1536295] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Julie Brasili
- Department of Chemical Engineering, University of Pittsburgh at Johnstown, Johnstown, PA, USA
| | - Korrin Fox
- Department of Chemical Engineering, University of Pittsburgh at Johnstown, Johnstown, PA, USA
| | - David Badamo
- Department of Chemical Engineering, University of Pittsburgh at Johnstown, Johnstown, PA, USA
| | - Gabriel Berghe
- Department of Chemical Engineering, University of Pittsburgh at Johnstown, Johnstown, PA, USA
| | - Rajendra Khanal
- Department of Physics, University of Pittsburgh at Johnstown, Johnstown, PA, USA
| | - Ramesh Singh
- Department of Chemical Engineering, University of Pittsburgh at Johnstown, Johnstown, PA, USA
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Petrescu E, Cirtoaje C, Danila O. Dynamic behavior of nematic liquid crystal mixtures with quantum dots in electric fields. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:399-406. [PMID: 29515953 PMCID: PMC5815281 DOI: 10.3762/bjnano.9.39] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 01/04/2018] [Indexed: 06/10/2023]
Abstract
The dynamic behavior of a mixture consisting of liquid crystalline 4-cyano-4'-pentylbiphenyl (5CB) and CdSe/ZnS quantum dots in electric fields was theoretically studied. The model was based on elastic continuum theory considering the interaction of the nematic molecules with the surrounding molecules, with the quantum dots and with the electric field. Experimental data obtained by dynamic measurements on a sample containing 0.89% (mass fraction) of CdSe/ZnS quantum dots revealed a decrease of the relaxation time compared to pure 5CB.
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Affiliation(s)
- Emil Petrescu
- University Politehnica of Bucharest, Department of Physics, Splaiul Independenţei 313, 060042, Bucharest, Romania
| | - Cristina Cirtoaje
- University Politehnica of Bucharest, Department of Physics, Splaiul Independenţei 313, 060042, Bucharest, Romania
| | - Octavian Danila
- University Politehnica of Bucharest, Department of Physics, Splaiul Independenţei 313, 060042, Bucharest, Romania
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Petrescu E, Cirtoaje C. Dynamic behavior of a nematic liquid crystal with added carbon nanotubes in an electric field. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:233-241. [PMID: 29441268 PMCID: PMC5789395 DOI: 10.3762/bjnano.9.25] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 12/21/2017] [Indexed: 05/21/2023]
Abstract
The dynamic behavior of a nematic liquid crystal with added carbon nanotubes (CNTs) in an electric field was analyzed. A theoretical model based on elastic continuum theory was developed and the relaxation times of nematic liquid crystals with CNTs were evaluated. Experiments made with single-walled carbon nanotubes dispersed in nematic 4-cyano-4'-pentylbiphenyl (5CB) indicated a significant difference of the relaxation time when compared to pure liquid crystal. We also noticed that the relaxation time when the field is switched off depends on how long the field was applied. It is shorter when the field is switched off immediately after application and longer when the field was applied for at least one hour.
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Affiliation(s)
- Emil Petrescu
- University Politehnica of Bucharest, Department of Physics, Splaiul Independenţei 313, 060042, Bucharest, Romania
| | - Cristina Cirtoaje
- University Politehnica of Bucharest, Department of Physics, Splaiul Independenţei 313, 060042, Bucharest, Romania
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Petrescu E, Cirtoaje C, Stan C. Dynamic behavior of a nematic liquid crystal mixed with CoFe 2O 4 ferromagnetic nanoparticles in a magnetic field. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:2467-2473. [PMID: 29234582 PMCID: PMC5704774 DOI: 10.3762/bjnano.8.246] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 10/27/2017] [Indexed: 06/07/2023]
Abstract
The dynamic behavior of a mixture of 4-cyano-4'-pentylbiphenyl (5CB) with 1% CoFe2O4 nanoparticles was analyzed. Experimental data indicate a high stability of the nematic director in the mixture compared to a reference 5CB sample in the magnetic field. The ferrite nanoparticles agglomerate forming long chains as observed in polarized microscopy images. These chains have a very high influence on the magneto-optic effect of the cell. When the magnetic field is applied on the mixture, the chains tend to align with the field direction but, due to their large size, they remain oriented obliquely between the support plates. Thus, the nematic molecules anchored on their surface can not reorient with the field and only a small distortion angle of the liquid crystal molecular director is observed. A comparison with a previously developed theoretical model confirms this small deviation.
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Affiliation(s)
- Emil Petrescu
- University Politehnica of Bucharest, Department of Physics, Splaiul Independenţei 313, 060042, Bucharest, Romania
| | - Cristina Cirtoaje
- University Politehnica of Bucharest, Department of Physics, Splaiul Independenţei 313, 060042, Bucharest, Romania
| | - Cristina Stan
- University Politehnica of Bucharest, Department of Physics, Splaiul Independenţei 313, 060042, Bucharest, Romania
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Zhou X, Zhang X, Xu S, Wu S, Liu Q, Fan Z. Evaluation of thermo-mechanical properties of graphene/carbon-nanotubes modified asphalt with molecular simulation. MOLECULAR SIMULATION 2017. [DOI: 10.1080/08927022.2016.1274985] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Xinxing Zhou
- Key Laboratory of Highway Construction and Maintenance Technology in Loess Region, Ministry of Transport, Shanxi Transportation Research Institute, Taiyuan, P.R. China
| | - Xiao Zhang
- Key Laboratory of Highway Construction and Maintenance Technology in Loess Region, Ministry of Transport, Shanxi Transportation Research Institute, Taiyuan, P.R. China
| | - Song Xu
- College of Civil Engineering, Fuzhou University, Fuzhou, P.R. China
| | - Shaopeng Wu
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, P.R. China
| | - Quantao Liu
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, P.R. China
| | - Zepeng Fan
- Key Laboratory of Highway Construction and Maintenance Technology in Loess Region, Ministry of Transport, Shanxi Transportation Research Institute, Taiyuan, P.R. China
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