Flexible, self-standing and patternable P(MMA-BA)/TiO2 photonic crystals with tunable and bright structural colors

To meet the requirement for flexible and transferrable optical equipment in life, developing flexible and self-supported photonic crystals (PCs) is substantially meaningful. Herein, we presented a facile and eco-friendly method to construct flexible, self-standing organic/inorganic hybrid 1DPCs with bright and tunable structural colors. 4-stack nanoparticle-based poly(methyl methacrylate-butyl acrylate) (P(MMA-BA)/TiO2) PCs are fabricated on low-surface-energy polypropylene substrates and covered with polydimethylsiloxane (PDMS) precursor afterwards. Through thermal treatment, the PCs together with cured PDMS can be easily lifted off without other post-treatment, and the color hue of the transferred 1DPC films holds good consistency with that before transfer. Tension test shows the self-standing PC film has good flexibility and better toughness than bare PDMS film. Based on this simple operation, patterned PC films can be achieved as long as placing a mask before covering the precursor. Due to organic vapor sensitivity of P(MMA-BA), this colorful self-supported PC structure shows distinguishable color change when exposing to different vapors, realizing naked-eye recognition of the solvents with the flexible organic/inorganic hybrid 1DPC device.