Work

Tunable Photonic Paints via Block Copolymer Self-Assembly and Refractive Index Engineering

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Structurally colored paints based on photonic microparticles offer an intriguing alternative to conventional pigment-based colorants but face persistent challenges related to limited color vibrancy and excessive light scattering. In this work, we present a scalable strategy to fabricate water-based photonic paints using poly(2-vinylpyridine)- block -poly(methyl methacrylate) (P2VP- b -PMMA) microparticles formed via confined self-assembly in emulsion droplets. These microparticles exhibit a concentric lamellar morphology, resulting in a photonic bandgap in the visible spectral region. Selective incorporation of 2,4,6-triiodophenol (TIPh) into the P2VP domains increases the refractive index contrast between microphase-separated domains, giving rise to tunable and more intense structural colors compared to additive-free microparticles. Detailed optical and structural characterization reveals a correlation among additive content, photonic bandgap position, and structural ordering. To reduce diffuse scattering and enhance color saturation, the broadband absorber Sudan Black B (C 29 H 24 N 6 ) is then coassembled within the microparticles. These photonic pigments are finally combined with a waterborne polyurethane binder to produce robust, vividly colored coatings. The binder improves film homogeneity, reduces interparticle scattering, and enhances mechanical integrity. This multicomponent approach─integrating refractive index engineering, pigment dispersion control, and optical absorption─enables the fabrication of structurally colored paints with improved vibrancy, uniformity, and tunability.

Source: ACS Applied Polymer Materials

DOI: 10.1021/acsapm.5c01430