Configuration-Dependent Liquid Crystal and Gel Behaviors of Tetraphenylethene-Containing Main-Chain Copolyesters

The construction of aggregation-induced emission-active (AIE-active) gelators with liquid crystal properties remains a challenge. Moreover, the effects of AIE configuration on liquid crystal, gel and AIE behaviors in one system are unclear. Herein, two main-chain liquid crystalline copolyester gelators with a single configuration of AIEgen TPE, mesogen biphenyl, and pendent amide groups are synthesized through melt polycondensation. Both copolyesters display smectic phase, while E-P20 possesses a wider temperature range of liquid crystal and a narrower layer distance owing to the more serious nonlinear “defect” of Z-TPE than E-TPE units. In addition, E-P20 and Z-P20 can form AIE-active gels with the minimum gelation concentration (MGC) values of 10 and 4 wt% in ethyl acetate mainly via hydrogen bonds between the pendent amide groups, respectively. These AIE-active gels show potential applications in temperature sensor, information storage, and so on.