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Nesterkina M, Kravchenko I, Hirsch AKH, Lehr CM. Thermotropic liquid crystals in drug delivery: A versatile carrier for controlled release. Eur J Pharm Biopharm 2024; 200:114343. [PMID: 38801980 DOI: 10.1016/j.ejpb.2024.114343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 05/29/2024]
Abstract
Responsive and adaptive soft-matter systems represent an advanced category of materials with potential applications in drug delivery. Among these, liquid crystals (LCs) emerge as multifunctional anisotropic scaffolds capable of reacting to temperature, light, electric or magnetic fields. Specifically, the ordering and physical characteristics of thermotropic LCs are primarily contingent on temperature as an external stimulus. This comprehensive review aims to bridge a notable gap in the biomedical application of thermotropic mesogens by exclusively focusing on drug delivery. Anticipated to inspire diverse ideas, the review intends to facilitate the elegant exploitation of controllable and temperature-induced characteristics of LCs to enhance drug permeation. Here, we delineate recent advancements in thermally-driven LCs with a substantial emphasis on LC monomer mixtures, elastomers, polymers, microcapsules and membranes. Moreover, special emphasis is placed on the biocompatibility and toxicity of LCs as the foremost prerequisite for their application in healthcare. Given the promising prospect of thermotropic LC formulations in a clinical context, a special section is devoted to skin drug delivery. The review covers content from multiple disciplines, primarily targeting researchers interested in innovative strategies in drug delivery. It also appeals to those enthusiastic about firsthand exploration of the feasible biomedical applications of thermotropic LCs. To the best of our knowledge, this marks the first review addressing thermotropic LCs as tunable soft-matter systems for drug delivery.
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Affiliation(s)
- Mariia Nesterkina
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Campus Building E 8.1, 66123 Saarbrücken, Germany.
| | - Iryna Kravchenko
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Campus Building E 8.1, 66123 Saarbrücken, Germany
| | - Anna K H Hirsch
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Campus Building E 8.1, 66123 Saarbrücken, Germany; Department of Pharmacy, Saarland University, Campus Building E8.1, 66123 Saarbrücken, Germany
| | - Claus-Michael Lehr
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Campus Building E 8.1, 66123 Saarbrücken, Germany; Department of Pharmacy, Saarland University, Campus Building E8.1, 66123 Saarbrücken, Germany
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2
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Veeraprakash B, Kesava Reddy M, Das BB, Lobo NP, Ramanathan KV, Narasimhaswamy T. Effortless Extraction of Structural and Orientational Information from 13C- 1H Dipolar Couplings for Thiophene Mesogens. J Phys Chem B 2023; 127:10912-10922. [PMID: 38063349 DOI: 10.1021/acs.jpcb.3c06176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Five molecular mesogens containing phenyl rings and thiophene are subjected to a detailed 13C NMR investigation. The first mesogen contains only phenyl rings, while the other four have thiophene with substitution at position 2 or 3. Two of these also have a spacer inserted between the thiophene and the rest of the core unit. The mesophase properties evaluated by complementary techniques reveal an enantiotropic nematic phase for all the cases and smectic C as well as Crystal J for a few mesogens. In addition to solution 13C NMR, the samples were studied using 1D and 2D solid-state 13C NMR experiments in the liquid crystalline phase. The chemical shifts and 13C-1H dipolar couplings obtained in the mesophase provided cutting-edge information about the molecular structure and orientation of the thiophene mesogens. Accordingly, dramatic differences in these parameters are noted for the mesogens, and consequently, the identification of 2- and 3-substituted thiophene mesogens is accomplished by a simple visual examination of the 2D spectra. Furthermore, for mesogens with a spacer between thiophene and the rest of the core, 13C chemical shifts and 13C-1H dipolar couplings showed remarkable variation, which was directly reflected in the order parameters. For instance, the order parameter (Szz) of thiophene in 2- and 3-substituted mesogens in which the spacer is absent is ∼0.63 whereas for those with spacer, it is reduced to ∼0.14-0.18. In comparison, the mesogen in which the core unit is made up of phenyl rings alone that is used to benchmark the characteristics of thiophene ordering showed an order parameter of ∼0.85. The study unambiguously demonstrates the supremacy of 13C NMR in extracting the structural and orientational information on mesogens in which thiophene is a constituent of the core unit.
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Affiliation(s)
- Bathini Veeraprakash
- Polymer Science and Technology, CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India
| | | | - Bibhuti B Das
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Nitin P Lobo
- Centre for Analysis, Testing, Evaluation & Reporting Services (CATERS), CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | | | - Tanneru Narasimhaswamy
- Polymer Science and Technology, CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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3
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Gradišek A, Cifelli M, Ancora D, Sepe A, Zalar B, Apih T, Domenici V. Analysis of Extra Virgin Olive Oils from Two Italian Regions by Means of Proton Nuclear Magnetic Resonance Relaxation and Relaxometry Measurements. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:12073-12080. [PMID: 33847493 PMCID: PMC8532148 DOI: 10.1021/acs.jafc.1c00622] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/31/2021] [Accepted: 04/02/2021] [Indexed: 05/07/2023]
Abstract
The interest in development of new non-destructive methods for characterization of extra virgin olive oils (EVOOs) has been increasing in the recent years. Among different experimental techniques, nuclear magnetic resonance (NMR) relaxation measurements are very promising in the field of food characterization and authentication. In this study, we focused on relaxation times T1 and T2 measured at different magnetic field strengths (namely, 2, 100, and 400 MHz) and 1H NMR T1 relaxometry dispersions directly on olive oil samples without any chemical/physical treatments. A large set of EVOO samples produced in two regions of Italy, Tuscany and Apulia, were investigated by means of 1H NMR relaxation techniques. The relaxation studies reported here show several common features between the two sets of EVOO samples, thus indicating that relaxation properties, namely, the ranges of values of T1 and T2 at 2 and 100 MHz, are characteristic of EVOOs, independently from the cultivars, climate, and geographic origin. This is a promising result in view of quality control and monitoring.
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Affiliation(s)
- Anton Gradišek
- Department
of Condensed Matter Physics, Jožef
Stefan Institute, 39 Jamova Cesta, SI-1000 Ljubljana, Slovenia
| | - Mario Cifelli
- Dipartimento
di Chimica e Chimica Industriale, Università
di Pisa, Via Moruzzi 3, 56124 Pisa, Italy
| | - Donatella Ancora
- Dipartimento
di Chimica e Chimica Industriale, Università
di Pisa, Via Moruzzi 3, 56124 Pisa, Italy
| | - Ana Sepe
- Department
of Condensed Matter Physics, Jožef
Stefan Institute, 39 Jamova Cesta, SI-1000 Ljubljana, Slovenia
| | - Boštjan Zalar
- Department
of Condensed Matter Physics, Jožef
Stefan Institute, 39 Jamova Cesta, SI-1000 Ljubljana, Slovenia
| | - Tomaž Apih
- Department
of Condensed Matter Physics, Jožef
Stefan Institute, 39 Jamova Cesta, SI-1000 Ljubljana, Slovenia
| | - Valentina Domenici
- Dipartimento
di Chimica e Chimica Industriale, Università
di Pisa, Via Moruzzi 3, 56124 Pisa, Italy
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4
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Lobo NP, Ramanathan KV, Narasimhaswamy T. 13 C NMR investigations of molecular order of rod-like, bent-core, and thiophene mesogens. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:988-1009. [PMID: 31770458 DOI: 10.1002/mrc.4972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/09/2019] [Accepted: 11/13/2019] [Indexed: 06/10/2023]
Abstract
In this review, methods to obtain the orientational order of topologically variant molecular mesogens using by one- and two-dimensional (2D) solid-state 13 C nuclear magnetic resonance (NMR) spectroscopy are described. Besides 13 C chemical shifts, the 13 C─1 H dipolar couplings measured from 2D-separated local field (SLF) technique are used for computing the order parameters of a variety of mesogens. The investigated molecules are composed of a variable number of rings in the core, that is, core ranging from simply one ring to five rings. Among the mesogens investigated, a special focus has been placed on mesogens with thiophene rings, which are gaining popularity as liquid crystalline organic semiconductors. The replacement of a phenyl ring by thiophene in the core has a dramatic influence on molecular topology, as observed from the measured order parameters. The review highlights the advantages of the 2D SLF method for understanding the local dynamics and for mapping the topology of mesogens through the measured order parameters. SLF NMR studies of as many as 24 molecular mesogens that vary in terms of the molecular structure as well as topology are covered in the review. Order parameters of the rings have been estimated from the 13 C─1 H dipolar couplings in the nematic, smectic A, smectic C, and tilted hexatic phases as well as in B1 and B2 mesophases of various mesogens. It is anticipated that, in the years to come, the 2D SLF method would provide advanced molecular information on structurally complex mesogens that are emerging in liquid crystal science through the incessant efforts of synthetic chemists. The mini review covers the orientational order of topologically variant molecular mesogens determined by 1D and 2D solid-state 13 C NMR spectroscopy. Accordingly, rod-like, bent-core, and thiophene mesogens were subjected to 2D SLF measurements to get the order parameters from which the topology was established. The replacement of phenyl ring by thiophene and its influence on order parameters as well as on molecular topology is also discussed.
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Affiliation(s)
- Nitin P Lobo
- Inorganic and Physical Chemistry, CSIR-Central Leather Research Institute, Chennai, India
| | - K V Ramanathan
- NMR Research Centre, Indian Institute of Science, Bangalore, India
| | - T Narasimhaswamy
- Polymer Science and Technology, CSIR-Central Leather Research Institute, Chennai, India
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5
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Study of Liquid Crystals Showing Two Isotropic Phases by 1H NMR Diffusometry and 1H NMR Relaxometry. CRYSTALS 2019. [DOI: 10.3390/cryst9030178] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this work, we report a study of two thermotropic liquid crystalline samples showing a not common mesophase behavior. The samples, namely a di-benzyloxy biphenyl derivative labelled 9/2 RS/RS, and a bimesogenic liquid crystal labelled L1, show a direct transition between two isotropic phases followed, at lower temperatures, by the optically isotropic, 3D structured, cubic phase. These systems have been investigated by means of 1H NMR diffusometry and 1H NMR relaxometry in order to characterize their isotropic–isotropic’–cubic mesophase behavior, mainly on the dynamic point of view. In particular, the temperature trend of the self-diffusion coefficients measured for both samples allowed us to significantly distinguish between the two isotropic phases, while the temperature dependence of the 1H spin-lattice relaxation time (T1) did not show significant discontinuities at the isotropic–isotropic’ phase transition. A preliminary analysis of the frequency-dependence of 1H T1 at different temperatures gives information about the main motional processes active in the isotropic mesophases.
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6
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Affiliation(s)
- Valentina Domenici
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Pisa, Italy
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7
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Lee S, Noda K, Hirata S, Vacha M. Position-Dependent Three-Dimensional Diffusion in Nematic Liquid Crystal Monitored by Single-Particle Fluorescence Localization and Tracking. J Phys Chem Lett 2015; 6:1403-1407. [PMID: 26263142 DOI: 10.1021/acs.jpclett.5b00488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Anisotropic mass diffusion in liquid crystals (LCs) is important from the point of both basic LC physics and their applications in optoelectronic devices. We use super-resolution fluorescence microscopy with astigmatic imaging to track 3D diffusion of quantum dots (QDs) in an ordered nematic LC. The method allowed us to evaluate the diffusion coefficients independently along the three spatial axes as well as to determine the absolute position of the QD with respect to the cell wall. We found variations of the diffusion coefficient along the different directions across the cell thickness and explained these as being due to changes of a tilt angle of the LC director. Close to the surface, the diffusion is slowed down due to the confinement effect of the cell wall. Overall, the QD diffusion is much slower than expected for a corresponding particle size. This phenomenon is suggested to originate from reorientation of the LC director in the vicinity of the particle.
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Affiliation(s)
- Seonik Lee
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama 2-12-1-S8-44, Meguro-ku, Tokyo, Japan
| | - Koushi Noda
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama 2-12-1-S8-44, Meguro-ku, Tokyo, Japan
| | - Shuzo Hirata
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama 2-12-1-S8-44, Meguro-ku, Tokyo, Japan
| | - Martin Vacha
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama 2-12-1-S8-44, Meguro-ku, Tokyo, Japan
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Reddy MG, Lobo NP, Varathan E, Easwaramoorthi S, Narasimhaswamy T. Intramolecular charge transfer interactions and molecular order of rod like mesogens. RSC Adv 2015. [DOI: 10.1039/c5ra22261c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Photophysical studies, VT-XRD and13C solid state NMR investigation of three ring based dimethylamino mesogens reveal intramolecular charge transfer, smectic Admesophase and molecular order.
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Affiliation(s)
- M. Guruprasad Reddy
- Polymer Laboratory
- CSIR-Central Leather Research Institute
- Chennai
- India-600020
| | - Nitin P. Lobo
- Chemical Physics Laboratory
- CSIR-Central Leather Research Institute
- Chennai
- India-600020
| | - E. Varathan
- Chemical Laboratory
- CSIR-Central Leather Research Institute
- Chennai
- India-600020
| | - S. Easwaramoorthi
- Chemical Laboratory
- CSIR-Central Leather Research Institute
- Chennai
- India-600020
| | - T. Narasimhaswamy
- Polymer Laboratory
- CSIR-Central Leather Research Institute
- Chennai
- India-600020
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9
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Domenici V, Milavec J, Zupančič B, Bubnov A, Hamplova V, Zalar B. Brief overview on 2H NMR studies of polysiloxane-based side-chain nematic elastomers. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2014; 52:649-655. [PMID: 24919664 DOI: 10.1002/mrc.4092] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 05/16/2014] [Accepted: 05/17/2014] [Indexed: 06/03/2023]
Abstract
This is a brief overview on recent studies on liquid crystalline elastomers (LCEs) based on polysiloxane chain, in the form of monodomain films, selectively (2)H-labeled in different parts of the LCE samples, i.e. on the crosslinker or mesogenic units. (2)H NMR spectroscopic techniques were used to measure the temperature dependence of the quadrupolar splittings, line widths and relaxation times, T(1) and T(2). From these data, several information about the orientational order parameter, S, of various LCE fragments, thermodynamic features of the isotropic-nematic transition and main motional processes could be generalized for this type of elastomers.
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Affiliation(s)
- Valentina Domenici
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, via Risorgimento 35, 56126, Pisa, Italy
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10
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Lobo NP, Phani Kumar BVN, Narasimhaswamy T, Mandal AB. (13)C NMR investigations and the molecular order of 4-(trans-4'-hexylcyclohexyl)-isothiocyanatobenzene (6CHBT). Phys Chem Chem Phys 2014; 16:14713-21. [PMID: 24919592 DOI: 10.1039/c4cp01569j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The static 1D (13)C and 2D Proton Encoded Local Field (PELF) NMR experiments are carried out in the nematic phase of a less viscous liquid crystal 4-(trans-4'-hexylcyclohexyl)-isothiocyanatobenzene (6CHBT) with a view to find orientational order. The PELF spectra provide better resolution which facilitates the assignment of cyclohexyl and phenyl ring carbons relatively easy. For the cyclohexyl unit, four pairs of dipolar splitting are clearly noticed in contrast to earlier reports on structurally similar mesogens where only two pairs of doublets are seen. The linear relationship between anisotropic chemical shifts and orientational order is established and semi-empirical parameters are obtained to aid the study of the order behaviour of 6CHBT over the entire nematic range. The data further fitted to the Haller equation and a reasonably good agreement is observed. The temperature dependence trends of orientational order parameters extracted for various carbons using (13)C-(1)H dipolar couplings with those of (13)C chemical shifts are compared. A gradual decrease in the order parameter is noticed for different molecular segments while traversing from the core to the aliphatic chain via the cyclohexyl ring. The notable decreasing trends of order parameters along the chain are observed similar to those of the corresponding phenyl cyclohexanes reported earlier.
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Affiliation(s)
- Nitin P Lobo
- Chemical Physics Laboratory, Council of Scientific and Industrial Research (CSIR)-Central Leather Research Institute (CLRI), Adyar, Chennai 600020, India.
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Gradišek A, Sebastião PJ, Fernandes SN, Apih T, Godinho MH, Seliger J. 1H–2H Cross-Relaxation Study in a Partially Deuterated Nematic Liquid Crystal. J Phys Chem B 2014; 118:5600-7. [DOI: 10.1021/jp502542q] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. Gradišek
- Jožef Stefan Institute, Jamova
39, SI-1000 Ljubljana, Slovenia
| | - P. J. Sebastião
- Centro de Física da Matéria Condensada, Av. Prof. Gama Pinto 2, 1649-003 Lisbon, Portugal
- Departamento
de Física, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
| | - S. N. Fernandes
- CENIMAT/I3N,
Departamento de Ciência dos Materiais, Faculdade de Ciências
e Tecnologia, UNL, 2829-516 Caparica, Portugal
| | - T. Apih
- Jožef Stefan Institute, Jamova
39, SI-1000 Ljubljana, Slovenia
| | - M. H. Godinho
- CENIMAT/I3N,
Departamento de Ciência dos Materiais, Faculdade de Ciências
e Tecnologia, UNL, 2829-516 Caparica, Portugal
| | - J. Seliger
- Faculty
of Mathematics and Physics, University of Ljubljana, Jadranska
19, SI-1000 Ljubljana, Slovenia
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Domenici V, Lelli M, Cifelli M, Hamplova V, Marchetti A, Veracini CA. Conformational Properties and Orientational Order of a de Vries Liquid Crystal Investigated through NMR Spectroscopy. Chemphyschem 2014; 15:1485-95. [DOI: 10.1002/cphc.201301036] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Indexed: 11/05/2022]
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Kim YK, Senyuk B, Shin ST, Kohlmeier A, Mehl GH, Lavrentovich OD. Surface alignment, anchoring transitions, optical properties, and topological defects in the thermotropic nematic phase of organo-siloxane tetrapodes. SOFT MATTER 2014; 10:500-509. [PMID: 24651889 DOI: 10.1039/c3sm52249k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We perform optical, surface anchoring, and textural studies of an organo-siloxane "tetrapode" material in the broad temperature range of the nematic phase. The optical, structural, and topological features are compatible with the uniaxial nematic order rather than with the biaxial nematic order, in the entire nematic temperature range -25 °C < T < 46 °C studied. For homeotropic alignment, the material experiences surface anchoring transition, but the director can be realigned into an optically uniaxial texture by applying a sufficiently strong electric field. The topological features of textures in cylindrical capillaries, in spherical droplets and around colloidal inclusions are consistent with the uniaxial character of the long-range nematic order. In particular, we observe isolated surface point defects - boojums and bulk point defects - hedgehogs that can exist only in the uniaxial nematic liquid crystal.
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Affiliation(s)
- Young-Ki Kim
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent, OH 44242, USA.
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