Engineering Achiral Liquid Crystalline Polymers for Chiral Self-Recovery

Flexible construction of permanently stored supramolecular chirality with stimulus-responsiveness remains a big challenge. Herein, we describe an efficient method to realize the transfer and storage of chirality in intrinsically achiral films of a side-chain polymeric liquid crystal system by combining chiral doping and cross-linking strategy. Even the helical structure was destroyed by UV light irradiation, the memorized chiral information in the covalent network enabled complete self-recovery of the original chiral superstructure. These results allowed the building of a novel chiroptical switch without any additional chiral source in multiple types of liquid crystal polymers, which may be one of the competitive candidates for use in stimulus-responsive chiro-optical devices.

Synthesis, Phase Behavior and Computational Simulations of a Pyridyl-Based Liquid Crystal System

A homologous set of liquid crystalline materials (Tn) bearing Schiff base/ester linkages were prepared and investigated via experimental and theoretical techniques. Terminal flexible groups of different chain lengths were connected to the end of phenylbenzoate unit while the other end of molecules was attached to the heterocyclic pyridine moiety. The molecular structures of the designed molecules were evaluated by FT-IR, NMR spectroscopic analyses, whereas their mesomorphic properties were investigated by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). They all exhibited dimorphic properties with the exception of the members having the shortest and longest terminal flexible chains (n = 6 and 16), which were monomorphic. The T16 derivative was further found possessing purely smectic A (SmA) mesophase while others have their lengths covered by nematic (N) phase. Moreover, the computational evaluation of the azomethine derivatives was carried out using a DFT approach. The polarity of the investigated derivatives was predicted to be appreciably sensitive to the size of the system. Furthermore, the Frontier molecular orbitals analysis revealed various distributions of electron clouds at HOMO and LUMO levels.

Nickel-phosphorus-boron amorphous alloy nanotubes improves the selective hydrogenation of furfural to furfuryl alcohol

Ni–P–B (NPB) amorphous alloy nanotubes were prepared for the selective liquid-phase hydrogenation of furfural to furfuryl alcohol. The content of P in NPB amorphous alloy nanotubes was adjusted by the initial NaH2PO2-containing liquid crystal system of non-ionic/anionic mixed surfactants. The promotion effect of an appropriate amount of P was mainly characterized by its large active surface area, ability for greater absorption of H, strong synergistic interaction, better stability, high conversion and catalytic selectivity. The NPB nanotubes exhibited higher hydrogenation activity when compared with the corresponding NPB nanoparticles, which might be dependent on the specific surface area, uniform active sites and tubular morphology of the catalysts.