Hierarchical chemomechanical encoding of multi-responsive hydrogel actuators 3D printing

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 7; no. 25; pp. 15395 - 1543
• Main Authors: Odent, Jérémy, Vanderstappen, Sophie, Toncheva, Antoniya, Pichon, Enzo, Wallin, Thomas J, Wang, Kaiyang, Shepherd, Robert F, Dubois, Philippe, Raquez, Jean-Marie
• Format: Journal Article
• Published: 25.06.2019
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c9ta03547h

Inspired by nature, we herein demonstrate a family of multi-responsive hydrogel-based actuators that are encoded with anisotropic swelling behavior to provide rapid and controllable motion. Fabrication of the proposed anisotropy-encoded hydrogel actuators relies on the high resolution stereolithography 3D printing of functionally graded structures made of discrete layers having different volume expansion properties. Three separate synthetic strategies based on (i) asymmetrical distribution of a layer's surface area to volume ratio via mechanical design, (ii) crosslinking density via UV photo-exposure, or (iii) chemical composition via resin vat exchange have been accordingly demonstrated for developing very smooth gradients within the printed hydrogel-based actuator. Our chemomechanical programming enables fast, reversible, repeatable and multimodal bending actuation in response to any immediate environmental change ( i.e. based on osmotic pressure, temperature and pH) from a single printed structure. A family of multi-responsive hydrogel-based actuators capable of rapid and controllable motion in response to any immediate environmental change is herein demonstrated towards the 3D-printing of functionally graded structures that are encoded with anisotropic swelling behavior.