Nematic Liquid Crystals

Jasiurkowska-Delaporte, Małgorzata; Kołek, Łukasz

doi:10.3390/cryst11040381

Cited by 4 publications

(4 citation statements)

References 13 publications

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“…For the endogenic impacts, molecular admixtures [ 7 ] or solid-state nanoparticle (NP) additions are notable [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Their influence is so significant that a new category of LC + NP nanocolloids and nanocomposites was established [ 8 , 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

The Dominance of Pretransitional Effects in Liquid Crystal-Based Nanocolloids: Nematogenic 4-methoxybenzylidene-4′–butylaniline with Transverse Permanent Dipole Moment and BaTiO3 Nanoparticles

Drozd-Rzoska,

Łoś,

Rzoska

2024

Nanomaterials

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The report presents static, low-frequency, and dynamic dielectric properties in the isotropic liquid, nematic, and solid phases of MBBA and related nanocolloids with paraelectric BaTiO3 nanoparticles (spherical, d = 50 nm). MBBA (4-methoxybenzylidene-4′–butylaniline) is a liquid crystalline compound with a permanent dipole moment transverse to the long molecular axis. The distortions-sensitive analysis of the dielectric constant revealed its hidden pretransitional anomaly, strongly influenced by the addition of nanoparticles. The evolution of the dielectric constant in the nematic phase shows the split into two regions, with the crossover coinciding with the standard melting temperature. The ‘universal’ exponential-type behavior of the low-frequency contribution to the real part of the dielectric permittivity is found. The critical-like pretransitional behavior in the solid phase is also evidenced. This is explained by linking the Lipovsky model to the Mossotti catastrophe concept under quasi-negative pressure conditions. The explicit preference for the ‘critical-like’ evolution of the apparent activation enthalpy is worth stressing for dynamics. Finally, the long-range, ‘critical-like’ behavior of the dissipation factor (D = tgδ), covering the isotropic liquid and nematic phases, is shown.

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Section: Introductionmentioning

confidence: 99%

The Dominance of Pretransitional Effects in Liquid Crystal-Based Nanocolloids: Nematogenic 4-methoxybenzylidene-4′–butylaniline with Transverse Permanent Dipole Moment and BaTiO3 Nanoparticles

Drozd-Rzoska,

Łoś,

Rzoska

2024

Nanomaterials

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“…A liquid crystal (LC) is an intermediate state between the solid state and the liquid state, which demonstrates the anisotropy and fluidity similar to that of crystals and liquids, respectively [1]. LCs are able to respond to various external stimuli (heat, electricity, light, and magnet force) resulting in the rearrangement of the anisotropic LC molecules (mesogens) accompanied by variations in optical properties, which demonstrates substantial significance for diverse applications, such as displays [2][3][4], optics [5], photonics [6], biosensors [7,8], and biomedicines [9].…”

Section: Introductionmentioning

confidence: 99%

Preparation and Orthogonal Analysis for Dual-Responsive Electrochromic Polymer Dispersed Liquid Crystal Devices

Xian

Ding

et al. 2023

Polymers

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In this work, we provide a fabrication method for dual-responsive electrochromic (EC) polymer dispersed liquid crystal (PDLC) devices. The EC PDLC device was developed by combing the PDLC technique and a colored complex formed via a redox reaction without a specific EC molecule in a simple preparation method. The mesogen played dual roles in the device for scattering in the form of microdroplets and participating in the redox reactions. Orthogonal experiments were performed with the acrylate monomer concentration, the ionic salt concentration, and the cell thickness as factors to investigate the electro-optical performance for the achievement of optimized fabrication conditions. The optimized device presented four switchable states modulated by external electric fields. The light transmittance of the device was changed by an alternative current (AC) electric field while the color change was realized by a direct current (DC) electric field. Variations of mesogen and ionic salt species can modulate the color and hue of devices, which solves the disadvantage of a single color for traditional EC devices. This work lays the foundation for realizing patterned multi-colored patterned displays and anti-counterfeiting via screen printing and inkjet printing techniques.

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“…In order to analyze phase transitions in thermotropic LCs, a technique known as differential scanning calorimetry (DSC) can be employed. [4][5][6][7][8][9][10][11] DSC is a technique that helps to find phase changes of matter using thermodynamics. In DSC, the instrument transfers energy to the sample in the form of heat, reaching a specified temperature using a chosen ramp rate, and then cools the sample to the beginning temperature.…”

Section: Introductionmentioning

confidence: 99%

Effect of Heating and Cooling on 6cb Liquid Crystal Using DSC Technique

Byrne,

Sharma

2023

ETJ

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In this research, details of the heating and cooling of the liquid crystal (LC) 4-cyano-4'-hexylbiphenyl (6CB) were collected through the use of Differential Scanning Calorimetry (DSC), and then analyzed with Logger Pro. The sample of 6CB was heated from -40 °C to 80 °C and then cooled to -40 °C again at a constant rate of 20 °C/min. DSC provided data for the time, temperature, and heat flow, which was used to calculate thermal speed, acceleration, and jerk, as well as the specific heat capacity at each point. Graphs of this data contain endothermic and exothermic peaks that indicate phase transitions, revealing information such as the enthalpy of the peak and the nematic range. One focus of this study was to compare 6CB to other liquid crystals that are part of the n-alkyl-cyanobiphenyl (nCB) family to see if the difference in tail length affects the behavior of the liquid crystal. Results show that 6CB may be of interest as an alternative to other liquid crystals for liquid crystal displays (LCD).

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Nematic Liquid Crystals

Abstract: The discovery of liquid crystals (LCs) is dated to the year 1888, when Friedrich Reinitzer reported his observation of the double melting points of cholesterol benzoate [...]

Cited by 4 publications

References 13 publications

The Dominance of Pretransitional Effects in Liquid Crystal-Based Nanocolloids: Nematogenic 4-methoxybenzylidene-4′–butylaniline with Transverse Permanent Dipole Moment and BaTiO3 Nanoparticles

The Dominance of Pretransitional Effects in Liquid Crystal-Based Nanocolloids: Nematogenic 4-methoxybenzylidene-4′–butylaniline with Transverse Permanent Dipole Moment and BaTiO3 Nanoparticles

Preparation and Orthogonal Analysis for Dual-Responsive Electrochromic Polymer Dispersed Liquid Crystal Devices

Effect of Heating and Cooling on 6cb Liquid Crystal Using DSC Technique

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