Cost‐Effective, Flexible, Hydrophobic, and Tunable Structural Color Polymeric Bragg Reflector Metastructures

Abstract The synthesis of flexible photonic materials, by sustainable and scalable methods, is proved to be a difficult task for the materials science and industrial communities. Alongside, the modern society has also grown a strong dependence on polymeric materials, demanding superpolymers that combine functionality and cost with superior after‐use properties. The path for accomplishing this aim is made possible by mimicking nature through the merging of self‐ordered nanostructures and a commodity thermoplastic, resorting to basic fabrication infrastructure. This work presents the development of a flexible material that exhibits tunable structural color due to its 3D polyethylene based nanonetwork. These nanonetworks are hydrophobic, and change color depending on the refractive index of the material filling their voids. This developed flexible metamaterial is projected to open opportunities for the fabrication of economically affordable (around 0.008 € cm⁻²) and solvent‐free photonic nanostructures with multipurpose applications such as sensing, energy saving, clothing, and photovoltaics, among others.