Iridescent structural colors from self-assembled polymer opal of polythiourethane microspheres

•PTUMS with narrow size distribution were prepared through a simple phase separation process.•Artificial opals with iridescent structural colors were obtained from the self-assembly of PTUMS.•The PTUMS particle sizes and corresponding structural colors can be easily adjusted.

Artificial structural color materials from self-assembled colloidal spheres, which are similar to natural opals, are currently a subject of extensive investigation. However, the shortage of available colloidal spheres, especially polymer spheres for building artificial opals is still a major restriction for their practical application. Herein, a new kind of artificial opals with iridescent structural colors were prepared from the self-assembly of novel polythiourethane microspheres (PTUMS). The PTUMS with narrow size distribution were prepared through a simple phase separation process. Particle sizes can be easily adjusted from 175 nm to 304 nm, which is important for the construction of tunable structural colors. Sufficient surface charges were obtained from the reaction between the terminal isocyanate groups and water. Thus, PTUMS can arranged into periodic opal structures through self-assembly process and generate iridescent structural colors. The present study provided an effective and convenient approach to prepare artificial structural color materials from new kind of polymer microspheres. This was very important for the practical application of artificial opals in coating and paints.

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