Robust and flexible free-standing polyimide/SiO x nanocomposite one-dimensional photonic crystals with high reflectance

Flexible free-standing one-dimensional photonic crystals (1DPCs) have attracted tremendous attentions owing to the simplest structure and promising applications in various fields. However, that most of flexible 1DPCs need dozens of stacks to achieve excellent optical properties and weak robustness in extreme environments hinder their practical applications. Herein, we prepare a series of robust, flexible free-standing polyimide (PI)/SiO x nanocomposite 1DPCs by solution process. Inorganic SiO x with low refractive index ( n ) is derived from the precursor perhydropolysilazane (PHPS) while the super-engineering plastic PI is served as the high-refractive-index constitution. Thanks to the high refractive index contrast (Δ n ) and uniform micromorphology of both materials, vivid PI/SiO x 1DPCs with tunable photonic bandgap are obtained and the reflectance is high up to 97% within only 9 layers. Due to the intrinsic properties and covalent binding between PI and SiO x layers, the free-standing nanocomposite remains stable in the wide range of – 196–200 °C and has no degradation of optical performance after bending deformation for 500 times. Additionally, PI/SiO x 1DPCs show great resistance to organic solvent, acid solution and ultraviolet (UV) radiation. Therefore, it is envisioned that the flexible free-standing PI/SiO x 1DPCs have great potential for applications in harsh environment. Graphical abstract