Sensitive fluorescence-responsive photonic crystals fabricated from AIE molecule embedded nanospheres for application in dual anti-counterfeiting textiles.

The preparation of anti-counterfeiting textiles is usually associated with laborious processes, high cost and environmental risks. In this work, the core-shell colloidal nanospheres composed of the polystyrene (PS) core with embedded aggregation-induced emission (AIE) molecules of tetraphenylethene (TPE) and the shell of densely crosslinked PS ((PS-TPE)@CPS) were designed and synthesized via emulsion polymerization. The patterned fluorescence-responsive photonic crystals (FRPCs) were then constructed using the (PS-TPE)@CPS nanospheres as building blocks on textile substrates via screen printing. Thanks to the compatibility and affinity of TPE with PS and its own AIE property, the TPE molecules enriched in the PS core and then aggregated and embedded within (PS-TPE)@CPS colloidal nanospheres. Confined by the polymer chains, the TPE molecules formed π-π stacking and exhibited AIE effect, while maintaining a stable conjugated structure. The FRPC anti-counterfeiting patterns constructed with the (PS-TPE)@CPS nanospheres exhibited angle-dependent structural colors under visible light and sensitive responsive fluorescence characteristic under ultraviolet light, realizing the double anti-counterfeiting effect. This approach to achieve anti-counterfeiting textile is simple, cost-effective, and environmentally friendly. The obtained FRPC patterns possess excellent optical properties and anti-counterfeiting functions, meeting the requirements for the sustainable structural coloration of textiles, and also promoting the practical application of responsive photonic crystal anti-counterfeiting textiles.