Dielectric and electro-optical properties of polymer-stabilized liquid crystal. II. Polymer PiBMA dispersed in MBBA

Tripathi, Pankaj Kumar; Pande, Mukti; Singh, Shri

doi:10.1007/s00339-016-0376-1

Cited by 24 publications

(5 citation statements)

References 17 publications

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“…To understand the possible origins of the intermolecular interactions that couple the LC orientations and PBLG chain organization, we compared the orientational responses of 5CB on the PBLG brushes to N -(4-methoxybenzylidene)-4-butylaniline (MBBA) (see Section S9). In contrast to 5CB, which possesses positive dielectric anisotropy and positive anisotropic polarizability, MBBA possesses negative dielectric anisotropy and positive anisotropic polarizability. ,, However, we found that MBBA and 5CB exhibited the same orientational response to the PBLG brushes, thus suggesting that dispersion interactions rather than dipolar interactions dominate the coupling of the organization of the PBLG brush to the LCs (see Section S9).…”

Section: Resultsmentioning

confidence: 63%

“…In contrast to 5CB, which possesses positive dielectric anisotropy and positive anisotropic polarizability, MBBA possesses negative dielectric anisotropy and positive anisotropic polarizability. 28,46,47 However, we found that MBBA and 5CB exhibited the same orientational response to the PBLG brushes, thus suggesting that dispersion interactions rather than dipolar interactions dominate the coupling of the organization of the PBLG brush to the LCs (see Section S9). (a,b,e,f,i,k) chloroform and (c,d,g,h,j,l 3.3.…”

Section: Resultsmentioning

confidence: 81%

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Using Liquid Crystals to Probe the Organization of Helical Polypeptide Brushes Induced by Solvent Pretreatment

et al. 2021

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Grafted polymer brushes form the basis of a versatile class of surfaces with properties that can be tailored via choice of the chemical functional groups or architecture of the grafted polymers. Here, we explore how treatment by solvents can program the organization of homopolymer brushes comprising helical poly(γ-benzyl-Lglutamate) (PBLG) and how the orientational behavior of liquid crystals (LCs) contacted with the brushes can provide fresh insights into brush organization. We treated PBLG brushes with either good (chloroform) or poor (acetone) solvents to form collapsed or teepee-like grafted polymer organizations, respectively. When supported on PBLG brushes with thicknesses [determined by atomic force microscopy (AFM)] of 50 nm, we found that collapsed and teepee-like brushes induced planar (parallel to surface) and homeotropic (perpendicular to surface) orientations of nematic LCs, respectively. By preparing solvent-pretreated brushes with a range of thicknesses (12−140 nm), and by combining insights based on AFM, Fourier-transform infrared spectroscopy and LCs, we found that a continuous change in tilt of the LC is accompanied by a continuous change in tilt of the PBLG chains, as influenced by the teepee-like organization. The role of PBLG chain orientation in dictating the LC orientation was confirmed by additional experiments in which PBLG brushes were thermally denatured. Finally, when using mixed solvents (mixtures of chloroform and acetone) to manipulate the PBLG brush organization, we observed LCs to exhibit patterned orientations on the micrometer scale, consistent with patterned orientations of the PBLG chains imprinted by droplets formed during the mixed solvent drying process. Overall, these results expand our understanding of the range of PBLG brush organizations that can be induced by solvent pretreatment and demonstrate the utility of LCs for imaging PBLG chain orientation within brushes.

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Section: Resultsmentioning

confidence: 63%

Section: Resultsmentioning

confidence: 81%

Using Liquid Crystals to Probe the Organization of Helical Polypeptide Brushes Induced by Solvent Pretreatment

et al. 2021

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“…The detail about the dielectric measurement for the liquid crystal has already been reported by us. [26]…”

Section: Preparation Of Lc Cellmentioning

confidence: 99%

Improved dielectric and electro-optical parameters of nematic liquid crystal doped with magnetic nanoparticles

et al. 2019

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This study investigates the effect of magnetic nanoparticles (NPs) on the weakly polar nematic liquid crystal (NLC). Different parameters of dielectric data were measured for both the homeotropic and planar aligned samples as a function of frequency and temperature and the substantial changes have been noticed for the doped systems. Dielectric permittivity has been increased after the dispersion of magnetic NPs in the pure NLC. Dielectric anisotropy has also been influenced by incorporating the magnetic NPs with the NLC molecules. These results were attributed to the dipole-dipole interaction between the magnetic nanoparticles and nematic liquid crystal molecules. Electro-optical study indicated the faster rise time and fall time of the doped systems as compare to pure NLC. Threshold voltage has been calculated and found to be decreased for the doped systems. Moreover, we have also calculated the rotational viscosity and the splay elastic constant for pure and the doped systems. Both the rotational viscosity and splay elastic constant of the doped systems are found to be considerably lower than those of pure NLC. Change in these properties has been explained on the basis of molecular disturbances created by the interaction between the magnetic nanoparticle and LC director. This study reveals that the inclusion of magnetic NPs in weakly polar NLC can be useful to enhance the basic properties of the weakly polar NLC and make it a promising material for many display applications.

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“…This reduces the driving voltage, lowers energy consumption, and shortens the response time of the liquid crystal (LC) molecules considering the external field for achieving a faster display sequence. 17,18 In addition to this, the impact of end groups, bridge bonds, and lateral substituents on the properties of LCs has been fully understood. New core structures such as heterocyclic and fused-heterocyclic rings have become the focus of molecular design.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Impact of carbon quantum dots on self-assembly and dielectric relaxation modes of a room temperature tri-component fluorinated antiferroelectric liquid crystal mixture

Iqbal,

Urbanska,

Dąbrowski

et al. 2023

Soft Matter

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Dielectric and electro-optical properties of polymer-stabilized liquid crystal. II. Polymer PiBMA dispersed in MBBA

Cited by 24 publications

References 17 publications

Using Liquid Crystals to Probe the Organization of Helical Polypeptide Brushes Induced by Solvent Pretreatment

Using Liquid Crystals to Probe the Organization of Helical Polypeptide Brushes Induced by Solvent Pretreatment

Improved dielectric and electro-optical parameters of nematic liquid crystal doped with magnetic nanoparticles

Impact of carbon quantum dots on self-assembly and dielectric relaxation modes of a room temperature tri-component fluorinated antiferroelectric liquid crystal mixture

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