Photonic Composite Liquid Crystal Polymerer Film Based On Dicyanodistyrylbenzene Fluorescent Unit

The dicyanodistyrylbenzene(DCS)unit is a ?-conjugated platform with abundant optical properties such as property of aggregation induced enhancement in emission(AIEE).Moreover,DCS has the properties of photoisomerization and photothermal characteristic,and its fluorescent color as well as wavelength various because of phase changes.As a consequence,a great deal of attention has been focused on fluorescent device and intelligent response material based on DCS.Photonic crystals(PCs)possess spatial periodicity in their dielectric constants on the length scale of the optical wavelength.The periodic electromagnetic modulation created by the PCs can yield a PSB(photonic stopband),by which PCs control and modulate the propagation of light.Commonly,materials composite of three dimension photonic crystal structure exhibit structural color which can be regulated by external stimulus.Therefore,photonic composite materials have always been an active part in the field of photoelectric functional material.In the topic studied,we firstly synthesized a polymerizable DCS unit which exhibit liquid crystal behavior in wide temperature range.A photonic composite film based on a luminescent DCS-based liquid crystal polymer network(LCN)was fabricated by using a silica colloidal crystal as a template.The film with bilayer structure which upper part is inverse opal structure has both fluorescent and reflection color.Research shows that the DSC units undergo irreversible Z/E photoisomerization under UV exposure,which can further be used to regulate PSB.Also a fluorescence enhancement phenomenon was observed in the photonic film due to the overlap between the reflection band and emission band of the fluorescent LCN.Based on the results,we fibericated nanopattern that can be observed in both reflection and fluorescent mode.On the other hand,three-dimension deformation of the photonic composite LC film has been studied.Research found that Z/E isomerization,internal stress and photothermal effect have common influence on the bending behavior of the film.In the first exposure cycle,DCS units underwent photoisomerization and internal stress released in the meantime,and the film went through irrversable deformation.In the following exposure cycles,reversible deformation occurred to the film because of photothermal effect.Meanwhile,hybrid alignment DCS-based liquid crystal polymer film is prepared as a control group to investigate the mechanism of bending behavior.In conclusion,in this topic,a polymerizable DCS unit for luminescent liquid crystals polymer film has been synthesized.Then,two systems have been constructed for study of the fluorescent display and bending behavior of DCS based luminescent liquid crystals polymer respectively.The topic research pioneers a different avenue to the construction and regulation of luminescent liquid crystals polymer materials with prospective application value in fluorescent displays and polymer actuators.