Patterned SiO2/Polyurethane Acrylate Inverse Opal Photonic Crystals with High Color Saturation and Tough Mechanical Strength

Patterned structural color photonic crystals (PCs) based on periodic photonic nanostructures have attracted great interest in developing high-performance sensors and other smart optical materials as well as tunable structurally colored fashion textiles. However, previously reported patterned PCs with both high color saturation and tough mechanical strength were difficult to achieve, which restricts their practical applications. Herein, arbitrarily patterned silica/polyurethane acrylate (SiO2/PUA) inverse opal photonic crystals (IOPCs) with high color saturation and tough mechanical strength were innovatively designed and fabricated by writing with photopolymerizable PUA "ink" on a self-assembled hollow SiO2 PC template. The high color saturation of the prepared SiO2/PUA IOPCs originated from the high refractive index contrast between the encapsulated air-filled core and the SiO2/PUA composite skeleton. The cross-linked flexible PUA matrix tightly warped the self-assembled hollow SiO2 nanospheres together, endowing the obtained SiO2/PUA IOPCs a structural color pattern with tough mechanical strength. The structural colors of SiO2/PUA IOPCs could be finely tuned by regulating their basic parameters, and a redshift in the resultant structural color was observed due to an increase in the lattice constant when increasing the core size and/or shell thickness of the hollow SiO2 nanospheres.