Photo-responsive hydrogel-based re-programmable metamaterials

• Published in: Scientific reports Vol. 12; no. 1; p. 13033
• Main Authors: Patel, Herit, Chen, Jiehao, Hu, Yuhang, Erturk, Alper
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 29-07-2022; Nature Publishing Group; Nature Portfolio
• Subjects: 639/166/988; 639/301/923/1027; Humanities and Social Sciences; Hydrogels; Irradiation; Mathematical models; multidisciplinary; Periodicity; Radiation; Science; Science (multidisciplinary); Wave propagation
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-022-15453-7

This paper explores a novel programmable metamaterial using stimuli-responsive hydrogels with a demonstration of bandgap formation and tuning. Specifically, a photo-responsive hydrogel beam that can achieve re-programmable periodicity in geometric and material properties through patterned light irradiation is designed. Hydrogels consist of polymeric networks and water molecules. Many unique properties of hydrogels, including bio-compatibility, stimuli-responsiveness, and low dissipation make them ideal for enabling re-programmable metamaterials for manipulating structural dynamic response and wave propagation characteristics. Bandgap generation and tunability in photo-responsive hydrogel-based metamaterial (in the form of a diatomic phononic chain) as well as the effects of system parameters such as light exposure pattern and photo-sensitive group concentration on the bandgap width and center frequency are systematically studied. In agreement with finite-element model simulations, it is observed that an increase in light exposure region size reduces both the bandgap width and center frequency, while an increase in the concentration of photo-sensitive group increases bandgap width, attenuation and reduces its center frequency. This work unveils the potential of stimuli-response hydrogels as a new class of low-loss soft metamaterials, unlike most other soft materials that are too lossy to sustain and exploit wave phenomena.