In a liquid crystal (LC) state, specific orientations and alignments of LC molecules produce outstanding anisotropy in structure and properties, followed by diverse optoelectronic functions Besides organic LC molecules, other nonclassical components, including inorganic nanomaterials, are capable of self-assembling into oriented supramolecular LC mesophases by non-covalent interactions Particularly, huge differences in size, shape, structure and properties within these components gives LC supramolecules higher anisotropy and feasibility Therefore, hydrogen bonds have been viewed as the best and the most common option for supramolecular LCs, owing to their high selectivity and directionality In this review, we summarize the newest advances in self-assembled structure, stimulus-responsive capability and application of supramolecular hydrogen-bonded LC nanosystems, to provide novel and immense potential for advancing LC technology

https://www.mdpi.com/2079-4991/11/2/448/pdf

Smart Supramolecular Self-Assembled Nanosystem: Stimulus-Responsive Hydrogen-Bonded Liquid Crystals.

The paper discusses mechanisms of molecular motion in lamellar chain molecular crystals of the stearic acid. Thermal calorimetry, dielectric and IR-spectroscopy methods indicate a phase transition ...

Topological solitons in crystals formed by aliphatic molecules with dimeric rings

This work deals with the use for the first time of waste spent glass as a new source of silicon and aluminum in the synthesis of highly ordered MCM-41 nanomaterials and also treats the method (namely direct and indirect) of its activation by copper under different mass ratios Si/Cu 60; 80 and 100. The evaluation of the activation method efficiency is tested against Gram-negative (E. coli) and Gram-positive (S. aureus and Bacillus cunis). The ordered MCM-41 nanomaterials were prepared by hydrothermal synthesis using the waste spent glass as silicon and aluminum sources. The silicon and aluminum needed for the synthesis of MCM-41 are extracted from waste spent glass by the alkaline fusion process. The copper is added to the MCM by two mentioned methods separately to obtain Cu-MCM-41. The resulting MCM were characterized by X-ray fluorescence (XRF), Inductively Coupled Plasma Optical Emission spectroscopy (ICP-OES), X-ray diffraction (XRD), Nitrogen adsorption-desorption, and Fourier transformed Infra-red spectroscopy (FTIR). Evaluation data revealed that the ordered mesoporous Cu-MCM-41 nanomaterials by both methods under different mass ratios Si/Cu are obtained. The high crystalline order is attributed to the mass ratio Si/Cu 100 for both methods. It is also noted that the specific surface areas of all mass ratios in both methods are up to 1000 m2 g−1. No relationship is found between surface area and substitution method or metal content. Indeed, the efficiency of copper incorporation method of Cu-MCM-41 synthesized under molar ratio (Si/C = 100) in their two different states calcined and un-calcined are applied as antibacterial inhibitors against Gram-negative (E. coli) and Gram-positive (S. aureus and Bacillus cunis). The results obtained by the application of Cu-MCM-41 materials as antibacterial inhibitors appear to be very promising. However, the indirect method shows a slight improvement in antibacterial inhibition compared to the direct method.

The Influence of the Incorporation Method and Mass Ratio of Copper on the Antibacterial Activity of MCM-41

Chain length effect on the structure and thermotropic properties of asymmetric solid catanionic complexes (CAC) built of cetyltrimethylammonium bromide (C16TABr) and saturated n-fatty acids (CnSFA,...

Chain length effect on the structure and thermotropic phase transitions of solid catanionic complexes built of cetyltrimethylammonium bromide and saturated n-fatty acids

A novel blue phase hydrogen-bonded ferroelectric liquid crystal (HBFLC) series has been synthesized from cholesteryl stearate (CHS) and p-n-alkyloxybenzoic acid (nOBA, where n = 2 to12). Blue phase (BP) liquid crystalline complex is a high potent material for next-generation optoelectronic devices. The structural, optical, and thermal properties of present HBFLC complexes have been characterized by X-ray diffraction techniques (XRD), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR), polarizing optical microscope (POM), and differential scanning calorimetry (DSC) techniques. The band gap energy of the present HBFLC complex (4.6 eV) is estimated by UV-Visible spectrometer. X-ray diffraction and scanning electron microscope (SEM) studies which confirm the monoclinic nature and morphology of the present complex. Phase diagram of the present CHS + nOBA is constructed from DSC data and the same is discussed. The lower homologous of CHS + nOBA HBFLC (n = 2 to 6) complex shows BPsm1, BPsm2, BPsm3 while higher homologous (n = 7 to 12) exhibiting orthogonal smectic A* (SmA*) character with blue phases. A noteworthy observation is that the identification of extended thermal span of smectic blue phases and induced SmA* phase in the present HBFLCs. Another important observation is that the widest BP range is reported in the present hydrogen-bonded ferroelectric nanoliquid crystalline (HBFNLC) complex which is more suitable for photonic devices. In addition, LC parameters such as, phase width, thermal stability factor, phase transition temperature with enthalpy value, and the origination of orthogonal phases in CHS + nOBA HBFLC complex is also reported.

Exploration of Induced Blue Phases and Orthogonal Smectic Batonnets in Hydrogen-Bonded Ferroelectric Nanoliquid Crystalline Complexes for Optoelectronic Devices

Structural and thermal properties of a solid-state binary mixture of long-chain cationic and anionic surfactants (so-called catanionic complexes) composed of cetyltrimethyl-ammonium bromide, [H3C–(CH2)15–N+(CH3)3]Br−(CTAB), and saturated fatty acid (FA), CH3(CH2)12COOH (lauric acid, kC12), are studied. To clarify the effect of intermolecular interactions on the crystalline structure and phase transitions in this class of supramolecular compounds, the 1 : 1 kC12-CTAB binary mixture is investigated by means of X-ray diffraction, differential scanning calorimetry (DSC), and temperature-variable Fourier transform infrared spectroscopy (FTIR). Based on the comparison of the obtained results with those of other CTAB-FA binary mixtures with different alkyl chain length mismatches, the possible molecular packing in the crystal phase of CTAB-FA complexes and the mechanism of successive phase transitions in the condensed state are proposed.

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FTIR and DSC Studies of Binary Mixtures of Long-Chain Aliphatic Compounds: Lauric Acid – Cetyl-trimethylammonium Bromide

Structural and thermotropic peculiarities of hydrogen-bonded liquid crystals confined in mesoporous molecular sieves

First application of CARS spectroscopy for visualization of probe liquid crystal (LC) molecules nanoconfined to mesoporous silica host is reported. Mesoporous molecular sieves (Al-MCM-41, KIT-6, an...

Natalia Shcherban

Papers

FTIR and DSC Studies of Binary Mixtures of Long-Chain Aliphatic Compounds: Lauric Acid – Cetyl-trimethylammonium Bromide

Structural and thermotropic peculiarities of hydrogen-bonded liquid crystals confined in mesoporous molecular sieves

Chain length effect on the structure and thermotropic phase transitions of solid catanionic complexes built of cetyltrimethylammonium bromide and saturated n-fatty acids

CARS imaging of nematic liquid crystal confined to mesoporous silica-based particles