Robust Self-Healing Magnetically Induced Colloidal Photonic Crystal Hydrogels

As important biological functions of many creatures, structural colors and self-healing features play crucial roles in the survival of organisms. Inspired by these features, the intelligent self-healing colloidal photonic crystals (CPCs) materials with stable structural colors are constructed here by immobilizing magnetically assembling Fe3O4@SiO2 colloidal nanoparticles into a self-repairing hydrogel matrix. The self-repairing hydrogels, prepared by using biodegradable material poly(1-vinyl-2-pyrrolidinone-co-acrylamide) modified with O-carboxymethyl chitosan (O-CMC), exhibit an outstanding mechanical property with favorable toughness and elasticity. Interestingly, one-dimensional Fe3O4@SiO2 chain structures embedded in the framework can maintain the stability of the photonic band-gap structure and its resultant bright structural colors. Furthermore, O-CMC contained in the matrix can supply plentiful carboxyl, amino, and hydroxyl functional groups which can form abundant intermolecular hydrogen bonds, and thus give the robust self-healing capability to the CPC colored hydrogels. On the basis of such CPCs hydrogels with bright structural colors and robust self-healing properties, a 3D flower pattern has been designed to realize arbitrary 3D configurable modeling. This work might constitute a promising simple way to fabricate structural colored CPC materials with a longer functional life, and thus extend their practical applications.