Structure Memory Photonic Crystals Prepared by Hierarchical Self-Assembly of Semicrystalline Bottlebrush Block Copolymers

Structure memory one-dimensional photonic crystals (1D PCs) with recyclable, remoldable, and self-healing properties are prepared by hierarchical self-assembly of semicrystalline bottlebrush block copolymers (SCBBCPs) with crystalline poly(ethylene glycol) and amorphous poly(n-butyl acrylate) as the side chains. The SCBBCPs are directly thermally self-assembled into first-order lamellar structures of hundreds of nanometers within a few minutes at 80 °C. 1D PCs are formed after confined crystallization of PEG within the first lamellar microdomain at 25 °C to form second-order lamellar structure of ca. 13 nm, which increases the refractive index contrast of the first-order lamellae. The prepared 1D PCs are structure memory, as they change reversibly from hierarchical lamellae to first-order lamellae and disordered structures by temperature and remember each structure at 25, 80, and 90 °C and above temperatures, respectively. Owing to the structure memory property, the 1D PCs show multifunctional properties such as temperature sensitive, self-healing, remoldable, and recyclable, which shows applications in patterning, printing, and anti-counterfeiting. The temperature-controlled preparation of structure memory 1D PCs is environmentally friendly, low cost, and convenient for operating.