Enhanced Orientation of Liquid Crystals Inside Micropores of Metal–Organic Frameworks Having Thermoresponsivity

Abstract

With the aim of controlling the orientation of liquid crystals (LCs) toward realizing external stimuli–responsive materials with tunable functionalities, we synthesized a composite of LCs and metal–organic frameworks (MOFs) by filling LCs into the pores of MOFs (LC@MOFs) for the first time. The included LCs interact with the MOFs through coordination bonds between the cyano groups of the LCs and the metal ions of the MOFs, enabling the orientation of the LC molecules inside the pores of the MOFs and the realization of birefringence of LC@MOFs. The three‐dimensional nanometer interstice frameworks maintained the LC orientation even at temperatures much higher than the isotropic phase transition temperature of bulk LCs. Furthermore, the orientational state changed upon heating or cooling, inducing temperature‐dependent birefringence. This study provides a new approach to the development of stimuli–responsive optical materials and stimuli–responsive MOFs.

Development of a Self-Healing Gel with Self-Healing Kinetics That Can Be Controlled by Heat

“…The ester linkages of the BP polymer were hydrolyzed partially by the protons formed in Figure 1 a as shown in Figure 1 c. The resultant partially hydrolyzed BP polymer having carboxylic acids was cross-linked by Zn 2+ via a coordinate bond [ 36 , 37 ] as shown in Figure 1 d. It was considered that the gelation was carried out by these reactions of the BP polymer, TiCl 4 , and zinc.…”