(494g) Achieving High Retraction Velocity in a Bioinspired Resilient Hydrogel

Synthetic hydrogels mimicking elastomeric biopolymers can have potential applications in soft-robotics and prosthetics. In biological species, elastomeric biopolymers such as resilin are responsible for power amplified activities, essential for locomotion, feeding, and defense. Here, we report a bioinspired novel hydrogel synthesized through a free radical polymerization reaction of hydrophilic acrylic acid (AAc) and methacrylamide (MAM) and hydrophobic poly(propylene glycol) diacrylate (PPGDA). In this gel, the PPGDA forms hydrophobic associations covalently connected by polymerized AAc and MAM. The balance between hydrophilic and hydrophobic components enable the gel to display an elastic modulus up to 100 kPa, stretchability up to 8.6 times, and resilience up to 98%. These gels can achieve high retraction velocity when released from the stretched state. The achieved reaction velocity and the corresponding acceleration are comparable to those observed in power amplified activities in nature, for example, jump of a locust or the appendage strike of a Mantis shrimp. In addition, the gel preserves its mechanical properties in a saline environment, which makes it a suitable candidate for novel applications viz. undersea soft-robotics.