Effects of terminal substituents on mesomorphic properties of Schiff base – ester mesogens and DFT calculations

Al-Hamdani, Uhood J.; Abdulwahhab, Hayder A.; Hussein, Kawkab A.

doi:10.1080/02678292.2022.2091803

Cited by 10 publications

(3 citation statements)

References 62 publications

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“…The above characterized process is shown in the supporting information . The Δ n values of LC mixtures ( M 0 , M 1 , M 2 , M 3 , M 4 ) were calculated from the measured phase retardation at 25 °C [ 31 ]. The viscoelastic constant ( γ 1 / K 11 ) values of all LC mixtures were calculated through transient current method by autronic-MELCHRS LCCS107 [ 37 ].…”

Section: Methodsmentioning

confidence: 99%

“…Based on previous theoretical research [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] on liquid crystals, it is known that molecular inherent parameters such as the polarizability, dipole moment, aspect ratio and biphenyl dihedral angle are closely related to the properties of LCs such as birefringence, dielectric anisotropy and liquid crystal phase transition. Therefore, we used density functional theory (DFT) to optimize the geometric configuration of the LC compounds F 0 – F 4 , and the relevant theoretical calculations obtained were used to correlate the relevant experimental results.…”

Section: Methodsmentioning

confidence: 99%

“…Subsequently, we selected the commercial high-Δ n LC mixture (HTD028200-100) as the parent formulation to investigate their solubility and their effects on the clearing point of the parent LC mixture. Finally, combined with DFT calculations [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ], we expect to lay a theoretical foundation for the study of the fluorination effect on the intrinsic properties of these benzoxazole LCs, such as molecular configuration, polarizability, dipole moment and aspect ratio, to correlate the influence of these compounds on the electro-optical properties such as birefringence, dielectric anisotropy and viscoelastic coefficient of high-Δ n LC mixture. The electro-optical properties of target fluorinated target compounds ( F 1 , F 2 , F 3 , F 4 ) and their mixtures with commercially available high birefringence LC mixture ( M 1 , M 2 , M 3 and M 4 ) could also be tuned via doping of QDs [ 33 ].…”

Section: Introductionmentioning

confidence: 99%

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Fluorination Improves the Electro-Optical Properties of Benzoxazole-Terminated Liquid Crystals in High Birefringence Liquid Crystal Mixtures: Experimental and Theoretical Investigations

et al. 2023

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Aromatic heterocyclic liquid crystal (LC) materials have received much attention from LC chemists for their high birefringence and large dielectric anisotropy, yet few have reported their properties in LC mixtures. In this work, a series of fluorinated benzoxazole liquid crystal compounds were synthesized to evaluate their electro-optical properties in high birefringence LC mixtures, with the expectation of further establishing the theoretical basis and experimental evidence for their applications in LC photonics. Firstly, the effects of the lateral fluorine substituent positions on the molecular synthetic yield, mesomorphic and solubility properties were comparatively investigated. Afterwards, we focused on the fluorination effects on the core electro-optical properties, including birefringence, dielectric anisotropy and further investigation of the viscoelastic coefficient of high birefringence LC mixtures. Research results showed that the benzoxazole liquid crystal compounds possess low melting points, wide nematic phase intervals and good solubility by appropriate lateral fluorine substitution, which is beneficial to further improve the electro-optical properties of high birefringence LC mixtures. Meanwhile, the theoretical and experimental results corroborate each other to well reveal the structure–property relationship. This study demonstrates that fluorination would promote promising applications of benzoxazole-terminated liquid crystals in emerging LC optical devices.

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Section: Methodsmentioning

confidence: 99%