2D Protein Supramolecular Nanofilm with Exceptionally Large Area and Emergent Functions

2D nanofilms assembled by pure protein with a macroscopic area and multiple functions can be directly formed at the air/water interface or at the solid surface at a timescale of several minutes. The multifunctionality of the nanofilm coating is demonstrated by both top-down and bottom-up micro-/nanoscale interfacial engineering, including surface modification, all-water-based photo/electron-beam lithography, and electroless deposition.