Deconvoluting the Optical Response of Biocompatible Photonic Pigments. Issue 34 (13th July 2022)

• Record Type: Journal Article
• Authors: Wang, Zhen; Chan, Chun Lam Clement; Haataja, Johannes S.; Schertel, Lukas; Li, Ruiting; van de Kerkhof, Gea T.; Scherman, Oren A.; Parker, Richard M.; Vignolini, Silvia
• Is Part Of: Angewandte Chemie international edition. Volume 61:Issue 34(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-07-13
• Subjects: Block Copolymers -- Confinement -- Inverse Photonic Glasses -- Self-Assembly -- Structural Color; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202206562
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: To unlock the widespread use of block copolymers as photonic pigments, there is an urgent need to consider their environmental impact (cf. microplastic pollution). Here we show how an inverse photonic glass architecture can enable the use of biocompatible bottlebrush block copolymers (BBCPs), which otherwise lack the refractive index contrast needed for a strong photonic response. A library of photonic pigments is produced from poly(norbornene‐ graft ‐polycaprolactone)‐ block ‐poly(norbornene‐ graft ‐polyethylene glycol), with the color tuned via either the BBCP molecular weight or the processing temperature upon microparticle fabrication. The structure–optic relationship between the 3D porous morphology of the microparticles and their complex optical response is revealed by both an analytical scattering model and 3D finite‐difference time domain (FDTD) simulations. Combined, this allows for strategies to enhance the color purity to be proposed and realized with our biocompatible BBCP system. Abstract : Inverse photonic glass microparticles, with colors across the visible spectrum, were prepared from a biocompatible bottlebrush block copolymer. The structure–optic relationship was investigated by i) a 3D phase‐field foam structural model and FDTD optical simulation, and ii) an analytical model of an assembly of Mie scatterers. From this, a strategy to improve the color purity was proposed and realized.