Abstract

Nature has developed a wide range of design strategies to produce materials with remarkable properties, including, for example, the dazzling optical effects of butterfly wings and the self-cleaning ability of the lotus leaf. Meanwhile, high transparency is critical to building windows, solar cell panels, electronic displays and much optical equipment. Taking a cue from Nature, where fabrication of structured materials follows a bottom-up approach, we synthesize and assemble nanoparticles by dip coating, spin coating, and spray coating on various substrates. When using nanoparticles of diameter less than 100 nm and control of particle shape and surface chemistry, we obtain transparent, superamphiphobic coatings that repel both water and oil. We demonstrate the application of such coatings in oil/water separation. By control the particle morphology and assembly process, we create the surface coating that is omni-transparent (or anti-reflective) from a wide range of viewing angles. Further, by spray coating of nanoparticles with diameter of 200-300 nm, we create a butterfly wing-like surface with quasi-amorphous photonic crystals that exhibit superhydrophobicity and angle-independent, structural colors.