Z/E Effect on Phase Behavior of Main-Chain Liquid Crystalline Polymers Bearing AIEgens

Abstract

The structure–property relationship of luminescent liquid crystalline polymers (LLCPs) with AIEgens has attracted much attention. However, the effect of the AIEgen configuration on the properties is still unclear because of the difficulty in designing LLCPs with a single configuration. In addition, it is expected that this effect can be amplified through constructing the AIEgen on the backbone of LLCPs. Herein, for the first time, we have synthesized two kinds of main-chain polyesters with a single configuration of an AIEgen, E-PM7 and Z-PM7, via melt polycondensation. Interestingly, E-PM7 shows two coexisting phases of rectangular columnar and smectic liquid crystalline phases, whereas Z-PM7 exhibits no liquid crystalline properties. Moreover, E-PM7 with AIE behavior and liquid crystalline properties can be used to prepare fluorescent patterns printed on flexible films and glass substrates through the photocyclization of AIE units, which endows this kind of material with promising applications ranging from anti-counterfeiting to information storage.

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

“…It is obvious that the temperature ranges of liquid crystal are 64.0 °C for E-P20 and 53.7 °C for Z-P20, which can be attributed to the more serious nonlinear "defect" of Zunits. The molar ratio of TPE and biphenyl units is 1:4 in Z-TPEcontaining polymer (named as Z-PM7) in our recent work, [25] while this ratio for Z-P20 is 1:1. It is rational that the effect of nonlinear "defect" of Z-units is less in Z-P20.…”

“…In other words, the configurations can be maintained completely at 130−145°C during polymerization. [25] The thermal stability of P20 has been investigated by thermogravimetric analysis (TGA). Figure S1 in the Supporting Information shows that the temperatures at 5% weight loss (T d ) are 290 °C for E-P20 and 289 °C for Z-P20, which suggests that both polymers exhibit good thermal stability.…”

“…[24] In our recent work, a pair of TPE isomers with two 6-hydroxyhexyl substituents has been successfully separated by simple column chromatography. [25] Moreover, the E-TPE-containing main-chain polymer (E-PM7) displays liquid crystal behavior while the Z-TPE-containing polymer (Z-PM7) is amorphous, which can be attributed to the more twisted structure for Z isomer than that for E one. [25] It is obvious that the TPE configuration is also one of the important factors for self-assembly behaviors.…”

A solid-state fluorescent probe for α,β-diamine based on tetraphenylethylene skeleton construction

“…27 Then, in the presence of potassium ferricyanide, TPE-2OH could be efficiently oxidized in toluene to afford the target compound DPEC . It should be noted that the synthesized TPE-2OH has cis and trans isomers, 28 which have the same luminescence characteristics and similar polarity. After oxidation, the double bond part in tetraphenylethylene formed a single bond of DPEC , which can rotate freely.…”

Fluorescent Polymers Conspectus

“…Luminous liquid crystals (LLCs) combining intrinsic light-emitting properties and liquid crystalline ordering have piqued interest in recent decades due to their potential applications as emissive liquid crystal displays (LCDs), organic light-emitting diodes (OLEDs), sensors, and optical information storage. [ 135 , 136 , 137 , 138 , 139 ] Xie et al [ 140 ], using AIE luminogens, were able to successfully manufacture a series of novel, highly efficient luminous liquid crystalline polymer (LCPs), namely poly{2,5-bis{[2-(4-oxytetraphenylethylene)-n-alkyl]oxycarbonyl}styrene}, with different chain lengths (m = 2, 4, 6, 8, 10, 12), as show in Figure 18 . LCPs are polymers with liquid crystal properties and frequently contain aromatic rings as mesogens.…”