Dependence of physical parameters on the size of silver nano particles forming composites with a nematic liquid crystalline material

Tripathi, Pratibha; Mishra, Mukesh; Kumar, Sandeep; Dąbrowski, R.; Dhar, Ravindra

doi:10.1016/j.molliq.2018.07.046

Cited by 31 publications

(5 citation statements)

References 42 publications

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“…Silver nanoparticles are also quite popular among the metal nanoparticles and have been widely used as nanodopants for the modification of LC physical properties [179] due to their high electric and thermal conductivity, nano-scale calorimetric effect, excellent chemical stability, and various medical and catalysts applications [184][185][186]. The thermodynamic, dielectric and electro-optic characteristics of a nematic LC (6CHBT) mixed with silver nanoparticles with different sizes have been studied by Tripathi et al They found that the first-order phase transition temperature of the mixture was marginally increased, while the dielectric permittivity, and elastic constants decreased compared to the pure LC [187].…”

Section: Modification Of Physical Properties Of Lc Materials By Nanodmentioning

confidence: 99%

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Perspectives in Liquid-Crystal-Aided Nanotechnology and Nanoscience

2019

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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. the observation of chirality from achiral molecules, resulting from sterically induced packing of the bent-core mesogens [10], such as ferroelectricity or the formation of helical superstructures in the B7 phase [14]. Thermotropic LCs are commonly constituted by single organic entities or mixtures thereof, which exhibit various mesophases at different temperatures or pressures [15], illustrated in Figure 1b. As the temperature rises, a typical thermotropic LC passes through higher ordered phases, also called soft crystals, the hexatic smectic phases with positional order as well as bond orientational order, through the fluid smectic phases (SmC and SmA), which exhibit both positional and orientational order, and finally to the nematic phase (N) with purely orientational order, into the isotropic phase. The number of different phases observed depends on the chemical composition, symmetry and order of the LC molecules. About 25 different thermotropic phases are known to date, and they are still increasing in number. Appl. Sci. 2019, 9, x FOR PEER REVIEW 2 of 47 unique effects of the observation of chirality from achiral molecules, resulting from sterically induced packing of the bent-core mesogens [10], such as ferroelectricity or the formation of helical superstructures in the B7 phase [14]. Thermotropic LCs are commonly constituted by single organic entities or mixtures thereof, which exhibit various mesophases at different temperatures or pressures [15], illustrated in Figure 1b. As the temperature rises, a typical thermotropic LC passes through higher ordered phases, also called soft crystals, the hexatic smectic phases with positional order as well as bond orientational order, through the fluid smectic phases (SmC and SmA), which exhibit both positional and orientational order, and finally to the nematic phase (N) with purely orientational order, into the isotropic phase. The number of different phases observed depends on the chemical composition, symmetry and order of the LC molecules. About...

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Section: Modification Of Physical Properties Of Lc Materials By Nanodmentioning

confidence: 99%

“…They found that the first-order phase transition temperature of the mixture was marginally increased, while the dielectric permittivity, and elastic constants decreased compared to the pure LC [187]. QDs are semiconductor nanoparticles in the range from two to 10 nanometres in diameter.…”

Section: Modification Of Physical Properties Of Lc Materials By Nanodmentioning

confidence: 99%

Perspectives in Liquid-Crystal-Aided Nanotechnology and Nanoscience

2019

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“…Various research reveals that nanomaterials play an important role in altering and improving the properties of LC molecules. A large number of LC-nanomaterial composites have been prepared and studied extensively to understand the effect of nanomaterials on the physical and chemical properties of LCs. ,− Dopants like quantum dots of CdSe, carbon, nanoparticles of BaTiO 3 , silver, gold, MgO, and single and multiwall carbon nanotubes were used. , Paul et al doped 0.5 wt % BaTiO 3 nanopowder in 6CHBT which led to a decrease in I–N transition and enthalpy value . Tripathi et al doped 0.6 wt % Silver nanoparticles of 5 and 100 nm size in 6CHBT LC and observed a nominal increase in I–N transition temperature and marginal decrease in dielectric anisotropy .…”

Section: Introductionmentioning

confidence: 99%

“…A large number of LC-nanomaterial composites have been prepared and studied extensively to understand the effect of nanomaterials on the physical and chemical properties of LCs. ,− Dopants like quantum dots of CdSe, carbon, nanoparticles of BaTiO 3 , silver, gold, MgO, and single and multiwall carbon nanotubes were used. , Paul et al doped 0.5 wt % BaTiO 3 nanopowder in 6CHBT which led to a decrease in I–N transition and enthalpy value . Tripathi et al doped 0.6 wt % Silver nanoparticles of 5 and 100 nm size in 6CHBT LC and observed a nominal increase in I–N transition temperature and marginal decrease in dielectric anisotropy . Patro et al doped 0.04 wt % COOH-functionalized multiwall carbon nanotube in 6CHBT which results in an increase of N–I transition temperature, average transition enthalpy, and entropy.…”

Section: Introductionmentioning

confidence: 99%

“… 19 Tripathi et al doped 0.6 wt % Silver nanoparticles of 5 and 100 nm size in 6CHBT LC and observed a nominal increase in I–N transition temperature and marginal decrease in dielectric anisotropy. 9 Patro et al doped 0.04 wt % COOH-functionalized multiwall carbon nanotube in 6CHBT which results in an increase of N–I transition temperature, average transition enthalpy, and entropy. For this composite, the value of dielectric anisotropy decreased, whereas relaxation frequency increased.…”

Section: Introductionmentioning

confidence: 99%

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Gold Nanorod-Induced Effects in a Mesogenic Compound 4-(trans-4-n-Hexylcyclohexyl) isothiocyanatobenzene

Lal,

Verma,

Chirra

et al. 2023

ACS Omega

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Gold nanorods (GNRs) have a capsule-like structure with different optical properties than spherical gold nanoparticles due to surface plasmon resonance. Liquid crystals (LCs) are mesogenic compounds having crystal-like orientation and liquid-like fluidity. They are important materials from a technological point of view. Both GNRs and LC compounds are anisotropic in shape and properties. Different nano entities show interesting results when dispersed in different liquid crystalline materials which are instrumental from the application point of view. In the present work, GNRs have been dispersed in nematic liquid crystalline materials, namely 4-(trans-4-n-hexylcyclohexyl) isothiocyanatobenzene (6CHBT). Calorimetric, texture, spectroscopic, and dielectric studies were carried out for a pure 6CHBT and its composites with GNRs. Different calorimetric and dielectric parameters such as transition temperature, enthalpy, heat flow, permittivity, dielectric strength, dielectric anisotropy, and relaxation frequency have been determined, and the effect of GNRs has been explored. This article gives an insight into the influence of GNRs on the morphology and anisotropic physical properties of the nematic liquid crystalline material.

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