掺杂手性螺烯化合物的胆甾相液晶复合体系的光驱动动态取向行为

Light-driven dynamic alignment behavior of cholesteric liquid crystalline composites doped with chiral overcrowded alkenes

将手性螺烯化合物掺杂到小分子向列相液晶中,制备了光响应胆甾相液晶(Cholesteric Liquid Crystal,ChLC)复合体系,以实现光驱动液晶分子取向技术。考察了不同强度的紫外光辐照下光响应ChLC的螺距变化规律,以及ChLC的动态取向行为。结果表明,光响应ChLC的螺距具有明显的紫外光强度寻址特性,ChLC会随着螺距的增长从混乱无序的焦锥织构转变为均一取向的平面织构,转变程度和转变速度随着紫外光强度的增加而增大,响应时间可从600s缩短至60s。但关闭紫外光后,由于螺距的剧烈变化,高强度紫外光所引导的平面织构会变回焦锥织构。采用多阶段制程的紫外光辐照方案,通过对不同阶段的紫外光强度进行适当调节,可以实现快速响应并且取向效果稳定的光驱动技术。

In order to realize light-driven dynamic alignment of liquid crystal（LC）molecules,photoresponsive cholesteric liquid crystalline composite was prepared by doping chiral overcrowded alkenes into achiral LC hosts.The variation of helical pitch and the dynamic homogeneous alignment of LC molecules in photo-responsive cholesteric liquid crystals（ChLCs）were investigated upon UV exposure with different intensities.The dynamic reconfiguration from focal conic to planar state was demonstrated based on the UV-intensity addressability of the helical pitch.The response time for dynamic homogeneous alignment of planar state can be accelerated from 600 sto 60 swith the increase of UV intensity,whereas the random alignment of focal conic state was developed in the absence of highpower UV exposure due to the sharp fluctuation of helical pitch.To properly modulate the intensity of UV light in multi-procedure protocols,the dynamic alignment technology with rapid response and stable homogeneousness was achieved.