Deconvoluting the Optical Response of Biocompatible Photonic Pigments

Area of Science:

• Materials Science
• Polymer Chemistry
• Optics

Background:

• Block copolymers are explored as photonic pigments, but environmental concerns like microplastic pollution necessitate sustainable alternatives.
• Biocompatible bottlebrush block copolymers (BBCPs) typically lack the required refractive index contrast for strong photonic properties.

Purpose of the Study:

• To develop environmentally friendly photonic pigments using biocompatible BBCPs.
• To overcome the low refractive index contrast limitation in BBCPs for photonic applications.
• To establish a structure-optic relationship for tunable color in BBCP-based photonic pigments.

Main Methods:

• Fabrication of a library of photonic pigments using poly(norbornene-graft-polycaprolactone)-block-poly(norbornene-graft-polyethylene glycol) BBCPs.
• Tuning color by altering BBCP molecular weight and processing temperature during microparticle fabrication.
• Utilizing an inverse photonic glass architecture to enhance photonic response.
• Employing analytical scattering models and 3D finite-difference time domain (FDTD) simulations to analyze structure-optic relationships.

Main Results:

• Demonstrated tunable color in BBCP-based photonic pigments through molecular weight and processing temperature control.
• Revealed the relationship between the 3D porous morphology of microparticles and their optical response.
• Successfully employed an inverse photonic glass architecture to amplify the photonic effect in BBCPs.
• Achieved enhanced color purity in the biocompatible BBCP system.

Conclusions:

• An inverse photonic glass architecture enables the use of biocompatible BBCPs as photonic pigments.
• Color tunability and enhanced color purity are achievable in BBCP-based photonic materials.
• This work provides a pathway for developing sustainable and high-performance photonic pigments.