Bio‐Based Multicompartment Photonic Pigments: Unlocking Non‐Iridescent Pure RGB Structural Colors for Versatile Chromatic Engineering

Abstract Non‐iridescent photonic glass pigments of block copolymers show great potential for sustainable structural coloration. However, the ability to create accurate RGB color mixtures for real‐world applications is limited by the prevalent use of non‐degradable, fossil oil‐derived components and the difficulty in achieving pure red hues. This work presents an alternative strategy for achieving more sustainable structural coloration by fabricating composite photonic pigments through controlled self‐assembly of water, vegetable oil, and biodegradable bottlebrush block copolymers (BBCPs) in a complex emulsion system. The obtained photonic balls feature unprecedented multicompartment structures characterized by a short‐range ordered assembly of water nanodroplets stabilized by the BBCPs, along with oil droplets stabilized by these nanodroplets, which substantially enhances resistance to Ostwald ripening. Furthermore, a new structural model is introduced to eliminate disordered scattering, successfully creating a pure red structural color and overcoming a long‐standing limitation in versatile chromatic engineering.