Angular Independent Photonic Pigments via the Controlled Micellization of Amphiphilic Bottlebrush Block Copolymers

TL;DR: In this article, porous microparticles with angular independent structural color are produced in a single, scalable step from an amphiphilic bottlebrush block copolymer by exploiting a novel controlled micellization self-assembly mechanism within emulsified toluene-in-water droplets.

Abstract: Photonic materials with angular independent structural colour are highly desirable because they offer the broad viewing angles required for application as colorants in paints, cosmetics, textiles or displays However, they are challenging to fabricate as they require isotropic nanoscale architectures with only short-range correlation In this article, porous microparticles with such a structure are produced in a single, scalable step from an amphiphilic bottlebrush block copolymer This is achieved by exploiting a novel controlled micellization self-assembly mechanism within emulsified toluene-in-water droplets By restricting water permeation through the droplet interface, the size of the pores can be precisely addressed, resulting in structurally coloured pigments Furthermore, the reflected colour can be tuned to reflect across the full visible spectrum using only a single polymer (Mn = 290 kDa) by altering the initial emulsification conditions Such photonic pigments have several key advantages over their crystalline analogues, as they provide isotropic structural coloration that suppresses iridescence and improves colour purity without the need for either refractive index matching or the inclusion of a broadband absorber