Anisotropic and self-healing hydrogels with multi-responsive actuating capability

Abstract

Inspired by smart biological tissues, artificial muscle-like actuators offer fascinating prospects due to their distinctive shape transformation and self-healing function under external stimuli. However, further practical application is hindered by the lack of simple and general routes to fabricate ingenious soft materials with anisotropic responsiveness. Here, we describe a general in situ polymerization strategy for the fabrication of anisotropic hydrogels composed of highly-ordered lamellar network crosslinked by the metal nanostructure assemblies, accompanied with remarkably anisotropic performances on mechanical, optical, de-swelling and swelling behaviors. Owing to the dynamic thiolate-metal coordination as healing motifs, the composites exhibit rapid and efficient multi-responsive self-healing performance under NIR irradiation and low pH condition. Dependent on well-defined anisotropic structures, the hydrogel presents controllable solvent-responsive mechanical actuating performance. Impressively, the integrated device through a healing-induced assembly way can deliver more complicated, elaborate forms of actuation, demonstrating its great potentials as superior soft actuators like smart robots.

The development of artificial muscle-like actuators is often hampered by the lack of general fabrication routes towards anisotropic responsive materials. Here, the authors fabricate anisotropic hydrogels by an in-situ polymerization strategy of a lamellar network, crosslinked by metal nanostructure assemblies.