This review summarizes the state-of-the-art development of Morpho butterfly wings used for various physical and chemical sensors.

An amorphous photonic structure dyeing system has been fabricated which endows non-iridescent color fabrics with color-tunable, robust, washable, self-healing and superhydrophobic properties by spray coating technique and heat treatment.

Use of structural colors for humidity sensors has great potential owing to their not being power driven and having distinct stimulus/color variation properties, but unfortunately most 1D, 2D or 3D photonic crystals have subtle nanostructures which are difficult to fabricate. Here we report a one-layer sub-micron thin film with bright color and high sensitivity to humidity, by spin coating of silk fibroin (SF) solution. The optical properties of the SF film caused by thin film interference can be easily tuned by the coating rates.Due to the high hydrophilicity of SF, the film exhibits fast responses with evident color variation in 5 s.And combined with the large peak red-shifts for more than 130 nm, such a thin film is superior to many other multilayered or photonic crystal based humidity sensors. Considering the good reversibility and durability, these low-cost but highly efficient SF spin coating sensors can realize colorimetric detection of humidity like pH indicator papers, and may have great potential in applications for anti-counterfeit labeling. Fig. 1 Characterization of as-produced SF films. (a) Reflection spectra for the films obtained at different spin-coating rates and their optical images (insets). (b) Time evolution of water contact angle on a SF film. (c) AFM height profile of the film obtained at 3000 rpm. The corresponding SEM image and surface mapping are shown as insets.This journal is