The encoding of structural colors in microparticles has undergone significant progress especially by confined colloidal or liquid crystal self-assembly; nevertheless, the use of these previous approaches related to confined colloidal self-assembly, have been prominently limited to 3D optical effects such as Bragg diffraction and Anderson localization (e.g., Adv. Mater., 27, 627, (2015); Adv. Mater., 26, 5801 (2014), Nat. Commun., 5, 3068 (2014); Angew. Chem. Int. Ed., 126, 2943 (2014)).

Meanwhile, various natural organisms including flowering plants (e.g.,Hibiscus Trionum flower) have advanced their colorization strategies to divide incoming white light into the spatially sequenced vivid colors, especially by using 2D grating diffractive motifs, which is conformably confined onto the curvature (i.e., floral iridescence). In work published in Advanced Materials (adma.201600425), S. J. Yeo et al. conceived a new idea for the artificial approach to mimicking this wonderful biological strategy and its practical application to the color encoding of colloidal particles.

In particular, the monodisperse and smooth surface of photoreconfigurable microspheres, produced by microfluidic technique, was deterministically textured with diverse surface relief gratings (SRGs) by means of “holographic photofluidization (see review paper: S. Lee et al., Adv. Mater., 24, 2069 (2012))”; the relevant optical phenomena, this is, curved surface-confined grating diffraction inspired by floral-iridescence, have been firstly detailed. Above all, it will act as an important role in greater labeling diversity of colloidal particles and better model of biologically inspired engineering not only for colloidal patching, but also for rational molding of light-flow.