Multi-stimuli-responsive programmable biomimetic actuator

TLDR

Small untethered actuators are useful in many fields, yet current designs are limited by single‑stimulus response and lack of programmable structural changes, hindering their adaptability and use in studying locomotion. The study introduces a multiresponsive, patternable actuator that responds to humidity, temperature, and light through programmable structural changes. The actuator is fabricated by a rapid, facile hydrogel microstamping process that precisely patterns graphene oxide films. The actuator demonstrates versatile motion, mimicking a hawk’s claw to grab a block, inchworm‑like crawling, and flower‑like twining, all governed by its geometry.

Abstract

Abstract Untethered small actuators have various applications in multiple fields. However, existing small-scale actuators are very limited in their intractability with their surroundings, respond to only a single type of stimulus and are unable to achieve programmable structural changes under different stimuli. Here, we present a multiresponsive patternable actuator that can respond to humidity, temperature and light, via programmable structural changes. This capability is uniquely achieved by a fast and facile method that was used to fabricate a smart actuator with precise patterning on a graphene oxide film by hydrogel microstamping. The programmable actuator can mimic the claw of a hawk to grab a block, crawl like an inchworm, and twine around and grab the rachis of a flower based on their geometry. Similar to the large- and small-scale robots that are used to study locomotion mechanics, these small-scale actuators can be employed to study movement and biological and living organisms.