Novel Retroreflective Structural Color Films Based on Total Internal Reflection Interference

Structural color materials have tremendous applications and been extensively investigated in the past decades. Most of them involve either nanoscale periodic photonic crystal structure or film interference mechanisms. Herein, we report a novel retroreflective structural color film (RSCF) based on a combined effect of interference and total internal reflection (TIR). The RSCF is consisted of a microscale polymer hemisphere array formed on the same polymer matrix. When exposed to white light illumination, the non-hemisphere-side of the film exhibits non-iridescent color under coaxial illumination and observation, and iridescent color under noncoaxial illumination and observation. In contrary, the hemisphere-side of the film does not show any colors regardless of coaxial or noncoaxial illumination and observation. Furthermore, an elastic polyurethane-based RSCF can exhibit dynamically and reversibly changing colors during uniaxial tensile/compressive deformation.