Fig. 10. (a) Schematic representation of the preparation of composite PVA/DBA coating films. Guest materials in the coating agents are encapsulated into the boronate networks of PVA and DBA upon solvent evaporation of the mixtures. Photographs of composite coating films before (b) and after (c) immersion in water for 2 h. These coating films were prepared on PS Petri dishes (4 cm in diameter) using coating agents containing erio green B (EG), tris(2,2′-bipyridyl)ruthenium(ii) chloride (Rubpy), Prussian blue (PB), and gold nanoparticles (AuNPs) as guest materials, respectively.