Hydrogen‐Bonded Liquid Crystals in Confined Spaces—Toward Photonic Hybrid Materials

Abstract

A series of hybrid materials based on chiral nematic mesoporous organosilica (CNMO) films infiltrated with liquid crystalline hydrogen-bonded assemblies is prepared and characterized with respect to the mutual manipulation of the photonic properties of the host and the liquid-crystalline behavior of the guest. Detailed differential scanning calorimetry studies reveal the impact of confinement on the mesomorphic behavior of the liquid crystalline assemblies in the pores of the CNMO films. The photonic properties of the chiral nematic mesoporous host can be controlled by changing the temperature or irradiating the films with UV light. These stimuli-induced phase transitions are accompanied by changes in the orientational order of the mesogens as revealed by 19 F NMR spectroscopy. The combination of confinement and changes in the molecular orientation in a unique hybrid material based on hydrogen-bonded liquid crystals and a porous host with a chiral nematic mesostructure is an interesting concept for the design of optical sensors, reflectors, or filters.

Electric field- and light-responsive oxadiazole bent-core polycatenar liquid crystals

“…Here, we characterize photochromism in the LC state. 16,43,45,75,76 When columnar A n LCs were irradiated by 350 nm light of 40 mW cm −2 intensity, their domain texture and birefringence disappeared within one second, as demonstrated in Fig. 5 in the example of A12 ; such changes were not observed for the cubic-phase compound A8 , either by optical microscopy or by SAXS.…”

Dynamic Kerr and Pockels electro-optics of liquid crystals in nanopores for active photonic metamaterials

“…Thus, similarly, as it has been demonstrated for liquid-infused porous structures with electrochemical actuation 85 and wetting changes, 86 as well as versatile multifunctional material behavior in general, 87 our study indicates that liquid crystal-infused nanoporous solids allow for quite simple fabrication of electro-active functional nanomaterials. The functionalization approach by capillarity-driven spontaneous imbibition of the liquid-crystalline melt in combination with tailorability of anodic aluminum oxide 41,88–90 and the availability of other self-organized, optically transparent mesoporous media 10,66,91,92 demonstrate also the versatile character of the presented material fabrication process.…”

Dynamic Kerr and Pockels Electro-Optics of Liquid Crystals in Nanopores for Active Photonic Metamaterials

“…Thus, similarly as it has been demonstrated for liquid-infused porous structures with electrochemical actuation 79 and wetting changes 80 as well as versatile multifunctional material behavior in general 81 our study indicates that liquid crystal-infused nanoporous solids allow for a quite simple fabrication of electroactive functional nanomaterials. The simple functionalization approach by capillarity-driven spontaneous imbibition of the liquidcrystalline melt in combination with tailorability of anodic aluminum oxide 36,[82][83][84] and the availability of other self-organized, optically transparent mesoporous media 10,60,85,86 indicates also the versatile character of the presented material fabrication process.…”