The effect of cross-linked chains of polymer network on the memory states of polymer stabilized ferroelectric molecules

Lahiri, T.; Majumder, Tapas Pal

doi:10.1016/j.polymer.2012.03.008

Cited by 6 publications

(6 citation statements)

References 39 publications

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“… Here, F is the free energy for such a mixture system which depends on many parameters such as tilt angle (θ), temperature, spontaneous polarization, interlayer interaction, electric field, and so on, which directly follow from the adoption of a harmonic potential. It is noted that the square of the amplitude of the rotational viscosity |γ θ 2 | fluctuates sinusoidally with period of t n = 2 nπ /ω, where n = 1, 2, 3,...; thus, PDLC molecules should have nearly zero rotational value as these t n . Due to this, to make a limited rotational torque on the LC director synched with the electrical field, a precise timing is necessary.…”

Section: Resultsmentioning

confidence: 99%

“…It is noted that the square of the amplitude of the rotational viscosity |γ θ 2 | fluctuates sinusoidally with period of t n = 2nπ/ω, where n = 1, 2, 3,...; thus, PDLC molecules should have nearly zero rotational value as these t n . 32 Due to this, to make a limited rotational torque on the LC director synched with the electrical field, a precise timing is necessary. Therefore, at some specific frequencies, the PDLC is capable of switching at speeds comparable to the oscillation of the AC field.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Effect of Noncovalent Interaction of a Polymer-Dispersed Liquid Crystal for Interferometric Applications over a Range of Low Frequencies

Hassanfiroozi

Huang

2019

ACS Appl. Polym. Mater.

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Polymer-dispersed liquid crystal devices modulate the amplitude and optical phase of light in response to an electrical stimulation. Due to the mismatch of the refractive indices of the E7 liquid crystal mixture and the UV curable epoxy resin, the composite film scatters light. The mixture film turns transparent when the refractive indices of the UV curable agent and the liquid crystal become almost the same. Polymer-dispersed liquid crystals have attracted notable attention because of their potential in a broad range of applications like displays, smart windows and shutters, and holography. We have reported a distinctive characteristic of a polymer-dispersed liquid crystal prepared over a range of low frequencies such as 4.6–4.75 Hz. The cell response exhibits a unique optical feature. We have interpreted these results in terms of molecular interactions between liquid crystal components and UV curable glue. In addition, the polymer-dispersed liquid crystal was justified in terms of a model equivalent electrical circuit. The device has many promising applications, such as phase shifting and heterodyne interferometers, optical switches, nematic main-chain elastomer systems, multistable smart windows, and electro-optical modulators.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Effect of Noncovalent Interaction of a Polymer-Dispersed Liquid Crystal for Interferometric Applications over a Range of Low Frequencies

Hassanfiroozi

Huang

2019

ACS Appl. Polym. Mater.

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“…ε ¯stands for the modified dielectric permittivity of the medium. Setting this value of D into equation (8), we find the modified dielectric permittivity for the system to be…”

Section: = + •mentioning

confidence: 99%

“…Both of these instabilities are detrimental to the prospect of commercializing FLCs in display activities. The first problem is adequately addressed with the help of polymer stabilization [7,8], but the second problem is somewhat complex and needs more exploration. Impurities found in FLCs are mainly in the form of foreign or host ions that are either created due to the host molecular dissociations or injected during the fabrication process of the sample.…”

Section: Introductionmentioning

confidence: 99%

Poisson–Boltzmann equation and electro-convective instability in ferroelectric liquid crystals: a mean-field approach

Lahiri¹,

Majumder²,

Ghosh³

2014

Phys. Scr.

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Commercialization of ferroelectric liquid crystal displays (FLCDs) suffers from mechanical and electro-convective instabilities. Impurity ions play a pivotal role in the latter case, and therefore we developed a mean-field type model to understand the complex role of space charges, particularly ions in a ferroelectric liquid crystal. Considering an effective ion-chirality relation, we obtained a modified Poisson-Boltzmann equation for ions dissolved into a chiral solvent like the ferroelectric smectic phase. A nonuniform director profile induced by the mean electrostatic potential of the ions is then calculated by solving an Euler-Lagrange equation for a helically twisted smectic state. A combination of effects resulting from molecular chirality and an electrostatically driven twist created by the ions seems to produce this nonuniform fluctuation in the director orientation. Finally, both theoretical and experimental points of view are presented on the prediction of this mean-field model.

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“…Anisotropic networks are abundant in nature and among man-made materials. For example, nematic elastomers [1] or actin-myosin assemblies in cells [2], and polymer-stabilized ferroelectric liquid crystals [3]. These networks are constructed from anisotropic building blocks, nematogens such as stiff rods or semiflexible polymers which are well modelled by wormlike chains (WLCs) [4].…”

Section: Introductionmentioning

confidence: 99%

Force–extension relation of cross-linked anisotropic polymer networks

Benetatos¹,

Ulrich²,

Zippelius³

2012

New J. Phys.

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Cross-linked polymer networks with orientational order constitute a wide class of soft materials and are relevant to biological systems (e.g., F-actin bundles). We analytically study the nonlinear force-extension relation of an array of parallel-aligned, strongly stretched semiflexible polymers with random cross-links. In the strong stretching limit, the effect of the cross-links is purely entropic, independent of the bending rigidity of the chains. Crosslinks enhance the differential stretching stiffness of the bundle. For hard crosslinks, the cross-link contribution to the force-extension relation scales inversely proportional to the force. Its dependence on the cross-link density, close to the gelation transition, is the same as that of the shear modulus. The qualitative behaviour is captured by a toy model of two chains with a single cross-link in the middle.

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The effect of cross-linked chains of polymer network on the memory states of polymer stabilized ferroelectric molecules

Cited by 6 publications

References 39 publications

Effect of Noncovalent Interaction of a Polymer-Dispersed Liquid Crystal for Interferometric Applications over a Range of Low Frequencies

Effect of Noncovalent Interaction of a Polymer-Dispersed Liquid Crystal for Interferometric Applications over a Range of Low Frequencies

Poisson–Boltzmann equation and electro-convective instability in ferroelectric liquid crystals: a mean-field approach

Force–extension relation of cross-linked anisotropic polymer networks

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