新型光响应胶体光子晶体研究

Photoresponsive photonic crystals have important potentials in many fields such as chromatic stealth materials, all-optical devices, etc. However, traditional photoresponsivity mainly concentrated on changing the refractive index or volume of photonic crystals through the alteration of one single component of the backbone material. Therefore, the wavelength of photonic band gap shift in those photoresponsivity systems can hardly be more than 40 nm, which greatly limits the application of photoresponsive photonic crystals. In this project, a series of new photoresponsive photonic crystals will be developed. Introducing host-guest supramolecular system into the photonic crystals, under the co-operation of covalent crosslinker, the dissociation of host-guest pairs which initiated by photo-irradiation will result in swelling of the photonic crystal hydrogels and red-shift of the photonic band gap. With the existence of photothermal agents or photoacids/photobases, photo-irradiation could be transformed into thermal or pH stimuli, which results in swelling of the corresponding responsive materials and wavelength shift of photonic band gap. Controlling the orientation of liquid crystal molecules inside photonic crystals by photo-irradiation, the anisotropic dielectric properties make the photonic band gap change with reorientation of liquid crystal molecules. The above works can much broaden the wavelength shift of photonic band gap through photoresponsivity. Furthermore, it opens an avenue for adjusting structural color with incident light, realizing complete photonic band gap in anisotropic photonic crystals.

光子晶体中光子带隙的光响应调节，在变色隐身材料、全光器件等领域有重要价值，但传统光响应调控手段只着重于光子晶体骨架中某单一组分的折光率或体积变化，使得光子带隙波长移动窄（<40 nm），且调控手段单一，极大限制了其实际应用。本课题拟开发一系列光子带隙光响应调控新方法：将主客体超分子体系引入光子晶体，利用光照使主客体解络合，结合共价键交联剂共同作用，使体积膨胀，光子带隙移动；用光热转换材料、光酸/光碱等与相应的响应性材料共同构筑光子晶体，光照后将光信号转变为热或pH等刺激信号，引发光子晶体缩胀，实现光子带隙宽波长范围移动；将特定液晶分子填充入光子晶体骨架，用线偏光或无偏振光照射，控制液晶分子有序排列取向，利用液晶分子排列后的折光率各向异性来实现光子带隙的调控。以上工作开展可实现光子带隙的宽波长范围光响应调控，还可初步探索结构色随入射光颜色改变，各向异性光子晶体中完全光子带隙的实现等重要问题。

光子晶体中光子带隙的光响应调节，在变色隐身材料、全光器件等领域有重要价值，但传统光响应调控手段只着重于光子晶体骨架中某单一组分的折光率或体积变化，使得光子带隙波长移动窄（<40 nm），且调控手段单一，极大限制了其实际应用。在本项目资助下，取得一系列创新性成果：1）利用光碱体系将光信号转变为化学信号，结合pH响应骨架材料实现209 nm的光响应光子带隙调控；2）基于-环糊精和叔丁基之间的主客体相互作用构筑超分子光子晶体，利用竞争性目标分子实现主客体之间的解络合，改变光子晶体尺寸，实现有机小分子金刚烷钠以及色氨酸手性异构体的显色裸眼检测；3）分别用-环糊精和四甲氧基偶氮苯作为主客体构筑超分子光子晶体，利用四甲氧基偶氮苯（Mazo）特殊的光学性质，即短波长光照（475 nm）变为反式，长波长光照（620 nm） 变为顺式。反式与环糊精络合，增加光子晶体水凝胶交联度，使其体积缩小，结构色波长蓝移；用长波长光照，则反之，获得结构色红移。即结构色随外界光波长同向变色。在以上体系中系统研究各体系因素（聚合物骨架交联度、光碱浓度、主客体浓度等）、光照条件等对光子晶体光响应行为的影响，阐明其工作原理及调控机制。共在Chem. Commun.，J. Mater. Chem. C等期刊上发表SCI论文4篇。在国际国内学术会议上做特邀报告2次，项目期内博士研究生毕业1人。