Tri-band responsive PS-PMMA/SMC photonic crystals for real-time information writing and coding

In this study, we fabricated a kind of tri-band responsive photonic crystals (TRPCs) for real-time information writing and coding. First, core-interlayer-shell nanoparticles (CISNPs) were synthesized via semi-continuous emulsion polymerization, with photobase generators grafted onto the shell of the CISNPs. The photonic crystals were obtained by a rapid method, spraying the CISNPs solution onto the substrate. Fluorescamine (FA) and diacetylene (DA) solutions were further sprayed onto the photonic crystal surface to obtain TRPCs, respectively. The TRPCs can produce color changes under the light of UVC, NIR, and UVA. According to the tri-band responsive behaviors, the TRPCs were used for real-time information writing and coding. By covering different masks, DA and FA solutions were sprayed on the assembled photonic crystal to write information. Then the written information was displayed after being exposed to the UVC, NIR, and UVA light. Furthermore, photonic crystals with different structural colors assembled by CISNPs with different particle sizes were coded according to various structural colors and fluorescence colors. In this paper, two methods of fabricating photo-responsive photonic crystals were combined, that is, modifying the nanoparticle assembled to form photonic crystals and adding photo-responsive substances into the photonic band gap, to increase the response density of the photonic crystals, which can be applied in more complex anti-counterfeiting and coding.