Giles Luke W, Marlow Joshua B, Butler Calum S G, Turpin Geosmin A, de Campo Liliana, Mudie Stephen T, Faul Charl F J, Tabor Rico F
School of Chemistry, Monash University, Clayton 3800, Victoria, Australia.
Phys Chem Chem Phys. 2020 Feb 21;22(7):4086-4095. doi: 10.1039/c9cp05463d. Epub 2020 Feb 7.
Light-responsive binary (azobenzene + solvent) lyotropic liquid crystals (LCs) were investigated by structural modification of simple azobenzene molecules. Three benzoic acid-containing azobenzene molecules 4-(4-(hydroxyphenyl)diazenyl)benzoic acid (AZO1), 3-(4-(hydroxyphenyl)diazenyl)benzoic acid (AZO2) and 5-(4-(hydroxyphenyl)diazenyl)isophthalic acid (AZO3) were produced with various amide substitutions to produce tectons with a variety of hydrophobicity, size and branching. The LC mesophases formed by binary (azobenzene + solvent) systems with low volatility solvents dimethylsulfoxide (DMSO) and N,N-dimethylformamide (DMF) as well as the protic ionic liquids ethylammonium formate (EAF) and propylammonium formate (PAF), were investigated using a combination of small-angle X-ray and neutron scattering (SAXS and SANS) as well as polarising light microscopy (PLM). Increasing alkyl group length was found to have a strong influence on LC phase spacing, and changes in the position of substitution on the benzene ring influenced the preferred curvature of phases. UV-induced trans to cis isomerization of the samples was shown to influence ordering and optical birefringence, indicating potential applications in optical devices.
通过对简单偶氮苯分子进行结构修饰，研究了光响应二元（偶氮苯+溶剂）溶致液晶（LCs）。制备了三种含苯甲酸的偶氮苯分子4-（4-（羟苯基）重氮基）苯甲酸（AZO1）、3-（4-（羟苯基）重氮基）苯甲酸（AZO2）和5-（4-（羟苯基）重氮基）间苯二甲酸（AZO3），并进行了各种酰胺取代，以制备具有不同疏水性、尺寸和支化的构造单元。使用小角X射线和中子散射（SAXS和SANS）以及偏光显微镜（PLM）相结合的方法，研究了由二元（偶氮苯+溶剂）体系与低挥发性溶剂二甲基亚砜（DMSO）和N，N-二甲基甲酰胺（DMF）以及质子离子液体甲酸乙酯铵（EAF）和甲酸丙酯铵（PAF）形成的LC中间相。发现增加烷基链长度对LC相间距有很大影响，苯环上取代位置的变化影响相的优先曲率。样品的紫外诱导反式到顺式异构化显示会影响有序性和光学双折射，表明在光学器件中有潜在应用。
