Preparation of biomimetic non-iridescent structural color based on polystyrene–polycaffeic acid core–shell nanospheres

Caffeic acid (CA), as a natural plant-derived polyphenol, has been widely used in surface coating technology in recent years due to its excellent properties. In this work, caffeic acid was introduced into the preparation of photonic band gap materials. By controlling the variables, a reasonable preparation method of polystyrene (PS) @polycaffeic (PCA)–Cu(II) core–shell microspheres was achieved: 1 mmol L−1 cupric chloride anhydrous (CuCl2), 3 mmol L−1 sodium perborate tetrahydrate (NaBO3·4H2O), 2 mmol L−1 CA and 2 g L−1 polystyrene (PS) were reacted at 50 °C for 10 min to prepare PS@PCA–Cu(II) core–shell microspheres through rapid oxidative polymerization of CA coated PS of different particle diameters. The amorphous photonic crystal structure was self-assembled through thermal assisted-gravity sedimentation, resulting in structural color nanomaterials with soft and uniform color, no angle dependence, stable mechanical fastness and excellent UV resistance.