Figure 4
From: Hydrogels with self-assembling ordered structures and their functions
(a) Schematic diagram of the structure of a photonic gel film and the tuning mechanism. The photonic gel film was prepared by self-assembly of a diblock copolymer (PS-b-QP2VP). The QP2VP gel layers swell or deswell (blue) in response to changes in aqueous solvent to tune the domain spacing, the refractive-index contrast and thus the wavelengths of light reflected by the stop band. (b) Scanning electron micrograph of a dry PS-b-QP2VP lamellar photonic film deposited on a silicon wafer. (c) Photograph of the photonic gel film immersed in water. Adapted from Ref. 58 (© 2007 NPG).
