Bubble evolution and manipulation revealed by reconfigurable shape-memory photonic crystals with tunable wettability

Understanding and controlling the behaviors of bubbles on the surface of macroporous materials (SMM) are of vital importance in the development of industrial catalysis, mass transfer, and membrane science. Using shape-memory photonic crystals (SMPCs) with tunable wettability as 3D/2D macroporous supports, we reveal for the first time the bubble evolution on the SMM by structure color. The evolution of oxygen bubbles generated by the film was accompanied by a red/blue shift structural color, which is convenient for analyzing the evolution process. The color contrast is produced by gas–liquid exchange triggered by Laplacian pressure in the macropores, which is regulated by surface wettability. Importantly, the pressure-induced reversible deformation of macropores adjusts surface wettability and promotes the corresponding gas–liquid exchange, enhancing the color contrast. It makes it possible to reveal bubble evolution in liquids with different wettability. Moreover, 2D bowl-shaped SMPCs with bubble anti-adhesion can be constructed by scraping 3D inverse opals. The reversible deformation of bowls can realize the switch between bubble adhesion and anti-adhesion. It improves our understanding of bubble evolution and inspires us to fabricate the next generation of interfacial catalysts, structured electrodes, and mass transfer interfaces.