Thermal, Optical, and Dielectric Analysis of Hydrogen-Bonded Liquid Crystals Formed by Adipic and Alkyloxy Benzoic Acids

Gopunath, A. J.; Chitravel, T.; Kavitha, C.; Prabu, N. Pongali Sathya; Mohan, M. L. N. Madhu

doi:10.1080/15421406.2013.839315

Cited by 19 publications

(4 citation statements)

References 40 publications

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“…These results confirm the intermolecular H-interactions between them. Moreover, the observation of three Fermi-resonance vibration bands of the H-bonded OH groups A-, B-, and C-types is also confirmation of the HBSMCs formation [35][36][37][38][39][40][41][42]. The A-type Fermi-band of complex A/2B12 is overlapped with that of the C-H vibrational peaks at 2920.0 to 2853.0 cm −1 .…”

Section: Ft-ir Characterizations Of 1:2 Hbsmcs Complexessupporting

confidence: 53%

Nematogenic Laterally Substituted Supramolecular H-Bonded Complexes Based on Flexible Core

Ahmed

Khushaim

2020

Crystals

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New laterally CH3-substituted series of 1:2 hydrogen-bonded supramolecular complexes (HBSMCs) based on flexible acid core were prepared and mesomorphically investigated. Mixtures were formed through H-bonded interactions between adipic acid (A) and 4-(2-(pyridin-4-yl)diazenyl-(3-methylphenyl) 4-alkoxybenzoate (Bn). Mesomorphic and optical properties were investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM), X-ray diffraction (XRD), and UV-spectroscopy. HBSMCs formed from 1:2 mol mixture of A:2Bn, where the base component (B) bearing different alkoxy chain lengths from n = 8 to 14. The new HBSMCs (A/2B) interactions were confirmed by Fermi-bands formation via FT-IR spectroscopy measurements. Results revealed that all prepared HBSMCs are enantiotropic, exhibiting induced nematic (N) phase. The XRD pattern confirmed the POM texture results. Moreover, a comparison was made between the new laterally HBSMC series based on flexible core and the previously analyzed laterally neat complexes.

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Section: Ft-ir Characterizations Of 1:2 Hbsmcs Complexessupporting

confidence: 53%

Nematogenic Laterally Substituted Supramolecular H-Bonded Complexes Based on Flexible Core

Ahmed

Khushaim

2020

Crystals

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“…The important evidence of the H-bonded interactions formation is the C=O, OH stretching vibration. It has been reported [41][42][43][44][45][46][47][48] that the presence of three Fermi-resonance vibration bands (A-, B-and C-types) of the H-bonded OH groups is a confirmation of the SMHB formation. The A-type Fermi-band of the complex A/2B10 is overlapped with that of the C-H vibrational peaks at 2922 to 2853 cm −1 .…”

Section: Ft-ir Characterizations Of 1:2 Smhblc Complexesmentioning

confidence: 93%

“…The change occurred in the UV-vis spectra of the base homologues (Bn), confirming the complexation. The complex A/2B12 absorption spectra (Figure 8) showed the maxima bands at 454 nm, which is attributed to the electronic transition from the highest occupied molecular orbitals (HOMO) to lowest unoccupied molecular orbital (LUMO), π-π transition [47][48][49][52][53][54].…”

Section: Photo-physical Studymentioning

confidence: 99%

Nematic Phase Induced from Symmetrical Supramolecular H-Bonded Systems Based on Flexible Acid Core

Ahmed

Khushaim

2020

Crystals

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New symmetrical 1:2 supramolecular H-bonded liquid crystals (SMHBLCs) interactions, A/2Bn, were formed between adipic acid and 4-(4′–pyridylazophenyl) 4″-alkoxybenzoates. Optical and mesomorphic behaviors of the prepared SMHBLC complexes were investigated using differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD). FT-IR spectroscopy was carried out to confirm the H-bond interactions of the prepared complexes via Fermi bands formation. Their photo-physical properties were investigated by UV-spectroscopy and the observed absorbance values were found to be mainly dependent on the length of the terminal alkoxy chain. Mesomorphic behaviour for all A/2Bn complexes revealed that all complexes are dimorphic-exhibiting enantiotropic mesophases with induced nematic phases, except for the long chain terminal complex which exhibits only a monomorphic smectic A phase. In order to investigate the effect of mesogenic core geometry on the mesophase properties, a comparison was established between the mesomeric behaviors of the present complexes and previously reported rigid core acid complexes. Finally, the XRD pattern confirmed the POM and DSC results.

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“…(3).Phase retardation (  ) of the liquid crystal was given by the birefringence n  , wavelength of light  and thickness of the sample d:[32][33][34] parameter of the liquid crystals is determined from the Kuczynski equation by using the direct measurement of birefringence values. The birefringence values are computed from equation (3)[35][36][37]. 0 ()…”

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confidence: 99%

Determination of Thermo Optical Parameters Using Image Analysis Technique in nBA: 7HB Hydrogen Bonded Liquid Crystals

Sastry¹,

Sarada²,

Mallika³

et al. 2015

IJIRSET

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In this paper, thermo optical properties of homologous series of hydrogen bonded liquid crystals: p-n alkyl benzoic acid (nBA): heptyl p -hydroxybenzoate (7HB) (where n=5 to 10) have been investigated by means of applying Image analysis technique in conjunction with Polarizing Optical Microscope. Textures of liquid crystal complexes are captured. The changes in textural features as a function of temperature are useful to compute the thermo optical properties. These microscopic textures are analysed using MATLAB software. The investigated thermo optical parameters are optical transmission, Absorption coefficient, Phase retardation, birefringence and order parameter. Experimentally, this is a simple technique to observe the behaviour of the optical parameters of different liquid crystals as a function of temperature.

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Thermal, Optical, and Dielectric Analysis of Hydrogen-Bonded Liquid Crystals Formed by Adipic and Alkyloxy Benzoic Acids

Cited by 19 publications

References 40 publications

Nematogenic Laterally Substituted Supramolecular H-Bonded Complexes Based on Flexible Core

Nematogenic Laterally Substituted Supramolecular H-Bonded Complexes Based on Flexible Core

Nematic Phase Induced from Symmetrical Supramolecular H-Bonded Systems Based on Flexible Acid Core

Determination of Thermo Optical Parameters Using Image Analysis Technique in nBA: 7HB Hydrogen Bonded Liquid Crystals

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