Preparation of Janus structural color sheets with flexibility, stability and low angle dependence based on textile

Structural colors with low angle dependence arising from photonic crystals are of increasing interest in various fields, such as sensing and display. In this study, the composite Poly(styrene-methyl methacrylate-acrylic acid) photonic crystals consisting of amorphous , simple cubic and face-centered cubic structures were facilely constructed by vacuum-assisted filtration self-assembly. Interestingly, this method enables microspheres to be assembled on flexible fabrics in a "bottom-up" manner, and different types of structural color sheets (single-sided coloring, double-sided homochromy or heterochromatic) can be obtained by controlling the dosage and particle size of the microspheres. In particular, the prepared structural color sheets are exceptionally bright and have low angle dependence. Subsequently, the photonic crystals in the flexible fabric were reinforced by the introduction of Poly(methyl methacrylate-butyl acrylate), which resulted in a significant improvement in the mechanical stability, the performance of which was demonstrated by water-rinsing, friction and folding tests. This study provides a novel way to prepare new structural color materials with bright and low angle dependence. In addition, this double-sided heterochromatic structural color sheet has potential applications in the display field.