Modulatable structural colors in rapid-curing high-performance hydrogels

Abstract

This study presents a rapid-curing methodology for fabricating high-performance hydrogels using a ternary copolymer system comprising 2-hydroxyethyl methacrylate (HEMA), N-vinylpyrrolidone (NVP), and N,N-dimethylacrylamide (DMAA). Through stoichiometric optimization, the hydrogels achieved a tensile strength of 6.14 MPa while retaining their structural integrity. As a proof-of-concept demonstration, this robust platform was engineered to integrate structural coloring as a novel, dye-free strategy for cosmetic contact lenses. The resulting lenses have advantages such as ultrafast fabrication, exceptional long-term stability (>200 days), and remarkable durability. Critically, vibrant and modulatable structural colors were readily constructed using colloidal silica-based photonic crystals, enabling precise control over optical appearance without sacrificing performance. The hydrogels further exhibit favorable optical properties, including high visible-light transmittance. Owing to its sophisticated assembly mechanism, the system displays structural colors with excellent resistance to photobleaching and fading. This work establishes a versatile material platform that combines rapid processability, mechanical robustness, and intrinsically tunable structural coloration, demonstrating its potential for advanced biomedical and optical applications.