Photonic pigments from white particles and black ink

In this paper, white silica nanoparticles with a diameter of 346 nm were prepared using the Stöber method. Mixed with different concentrations of black ink, the silica nanoparticles were self-assembled into structurally coloured photonic crystal films by gravity sedimentation at different temperature. The effects of temperature, the concentration of black ink and the viewing angle on the structural colour were investigated. The result showed structural colours can be produced by mixing white silica particles and commercial black ink, and this provided a novel strategy to make non-iridescent photonic pigments. (paper)