Effect of pi–pi stacking on the self-assembly of azomethine-type rod–coil liquid crystals
writer：Yi Liu, Guozhu Zhan, Xinhui Zhong, Yingfeng Yu* and Wenjun Gan
keywords：azomethine, pi–pi stacking interaction, rod-coil, self-assembly
source：期刊
specific source：Liquid Crystals
Issue time：2011年
The role of pi–pi stacking in the molecular self-assembly behaviour, the phase transitions and the fluorescent properties was investigated for coil–rod–coil liquid crystals with two ethylene oxide coil units and aromatic azomethine rod units. Three kinds of rod–coil liquid crystals with different rod units were synthesised and characterised by differential scanning calorimetry (DSC), polarised optical microscopy (POM), X-ray diffraction (XRD), transmission electronic microscopy (TEM), absorption and photoluminescence. With strong pi–pi stacking interaction between coplanar molecules, fibril structure in solution is formed while the fluorescent emission shows a rapid increase of the intensity of short wavelength with the increase of solution concentration. Spherical aggregations in solution are formed with the increase of the twisting of the rod segment plane, which decreases the pi–pi stacking interaction and thus enlarges the intermolecular spacing. Simulation work carried out in Material Studio corresponds well with the experiment results of aggregations and phase transitions.