Fabrication Of Responsive Inverse Opal Photonic Crystal Materials And Research On Information Encoding Behavior

Photonic crystals(PCs),as a special optical material,have become a research hotspot as smart materials combining optical signals and information technology because of their periodically arranged internal structure that can perform specific modulation of photon motion.The ordered structure of photonic crystal materials on the microscopic scale makes the motion of photons in specific wavelength bands constrained in them,forming the special optical property of photonic band gap(PBG),and it is the existence of photonic band gap that gives photonic crystal materials with efficient and vivid structural colors.Compounding with responsive materials,photonic crystals that respond to external environmental stimuli in real time can be constructed,and external conditions such as light,heat,electricity,and magnetism can be used to modulate the photonic band gap and express specific optical information,expanding the future research and application prospects of photonic crystals.Inverse opal photonic crystals(IOPCs)are constructed with periodically arranged holes in a dielectric material,and the resulting photonic crystal materials have higher saturation of structural color and higher sensitivity of responsiveness.Thus,this paper took the fabrication of responsive inverse opal photonic crystals as the core.We combined the modulation of the structural color of photonic crystals with the change of the chemical color of the responsive substrate material,to design and prepare multi-optical real-time modulated inverse opal photonic crystal materials.We investigated their multiple optical response performance,and exploited their conversion between colors to explore the optical signal encoding behaviors such as multiple information display and information recognition.The main contents include:1.Preparation and application of ultraviolet/near-infrared light real-time modulated inverse opal photonic crystal films.By etching off the silica photonic crystal template in a temperature-sensitive hydrogel with the addition of the photochromic molecule naphthopyran(NP),we prepared the UV/NIR light dual-responsive inverse opal photonic crystal films.We investigated its duallight response performance,and prepared a series of inverse opal photonic crystal information identifiable labels based on the UV/NIR light real-time tunable performance.Irradiated by UV light,the transparent hydrogel matrix turned red due to the presence of the photochromic molecule naphthopyran.At the same time,the green structure color of the inverse opal photonic crystals superimposed with the red chemical color of the hydrogel made the inverse opal photonic crystals with added naphthopyran(IOPCs/NP)appear yellow.Irradiated by near-infrared light,the structure color of the inverse opal photonic crystals changes from green to blue due to the volume contraction of the temperature-sensitive hydrogel.When irradiated by both UV and NIR light,the blue structure color of the inverse opal photonic crystals was superimposed with the red chemical color of the hydrogel,and the IOPCs/NP would finally appear purple.In this way,we achieved the real-time color conversion of the inverse opal photonic crystals under different light sources.Based on this,we designed and prepared a series of information identifiable labels with multiple colors under UV and NIR light,and explored the application cases in multiple information anti-counterfeiting and information encoding.2.Fabrication and research on photoresponse behavior of multimodal UVresponsive inverse opal photonic crystal beads arrays.We prepared photonic crystal beads by microfluidic method,filled with polyacrylamide hydrogels added with naphthopyran(NP),diphenylanthracene(DPA),and mixed naphthopyran and diphenylanthracene(NP-DPA),so that we obtained three different UV response modes of inverse opal photonic crystal beads after hydrofluoric acid etching.The inverse opal photonic crystal beads added with naphthopyran(IOPCs/NP)exhibited a superimposed color mode due to the superposition of structure color and chemical color after UV light irradiation due to the photochromic effect of NP,but presenting a dark mode when being irradiated by fluorescent light.The inverse opal photonic crystal beads added with diphenylanthracene(IOPCs/DPA)exhibited a fluorescence mode by emitting fluorescence under UV light,while the fluorescence disappeared immediately after the removal of UV light,showing the initial structure color mode.The inverse opal photonic crystal beads added with both naphthopyran and diphenylanthracene components(IOPCs/NP-DPA)emitted fluorescence under UV light,presenting a fluorescent mode,and maintained the superposition of photochromic chemical color and structure color after the UV light was removed,showing a superimposed color mode.It would return to the initial structure color mode after a certain time in visible light.We constructed beads arrays containing specific information by the above three kinds of inverse opal photonic crystals,which can be transformed between structure color,superimposed color,fluorescence and dark mode under different action times of UV light to express specific information under different circumstances.We investigated separately the photoresponsive properties of three kinds of inverse opal photonic crystal beads,and prepared various information arrays to explore the application method in information encryption and information display.