Tuning helical twisting power and photoisomerisation kinetics of axially chiral cyclic azobenzene dopants in cholesteric liquid crystals

被引：15

作者：

Zhou, Mengyi ^{[1
]}

Lu, Hongbo ^{[1
,2
]}

Zhang, Xinmin ^{[1
]}

Zhang, Qiang ^{[1
]}

Xu, Miao ^{[1
,2
]}

Zhu, Jun ^{[1
,2
]}

Zhang, Guobing ^{[1
,2
]}

Ding, Yunsheng ^{[1
,2
]}

Qiu, Longzhen ^{[1
,2
]}

机构：

[1] Hefei Univ Technol, Acad Optoelect Technol, State Key Lab Adv Display Technol, Key Lab Special Display Technol,Minist Educ,Natl, Hefei, Anhui, Peoples R China

[2] Hefei Univ Technol, Sch Chem & Chem Engn, Key Lab Adv Funct Mat & Devices, Hefei, Anhui, Peoples R China

来源：

LIQUID CRYSTALS | 2019年 / 46卷 / 15期

基金：

中国国家自然科学基金;

关键词：

Cyclic azobenzenes; chiral dopants; cholesteric liquid crystals; photoisomerisation; helical twisting power; LIGHT; DRIVEN; CONFORMATION; REFLECTION; DIMERS; GREEN; STATE; RED;

D O I：

10.1080/02678292.2019.1614235

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Significant attention has been paid to improve the helical twisting power (beta) and Delta beta between the two different isomers of axially chiral azobenzene dopants in cholesteric liquid crystals (CLCs); however, the correlations between the vales (beta and Delta beta) with the molecular structures as well as photoisomerisation kinetics are far from clear. In this study, a series of binaphthyl-azobenzene cyclic dopants R1-R3 with different lengths of alkoxy chain was synthesised, which exhibited photochemically reversible trans-cis isomerisation in both organic solvents and liquid crystal hosts. When doping into a nematic liquid crystal, dopant R2 with one linking alkoxy group showed the highest values of beta and Delta beta. The results revealed that the beta value was related to the dihedral angle between two naphthyl planes and the miscibility between the dopants and the host molecule. Moreover, Delta beta was also depended on the photoisomerisation quantum yields. With increasing length of alkoxyl chain, the photoisomerisation rate constant of dopants increased upon ultraviolet irradiation and decreased for the reverse process upon visible light irradiation either in isotropic acetonitrile or in CLCs. These results enable the precise tuning of the pitch and selective reflection wavelength of CLCs. [GRAPHICS] .

引用

页码：2181 / 2189

页数：9

共 55 条

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