Untethered stimuli‐responsive soft materials with programmed sequential self‐folding are of great interest due to their ability to achieve task‐specific shape transformation with complex final configuration. Here, reversible and sequential self‐folding soft actuators are demonstrated by utilizing a temperature‐responsive nanocomposite hydrogel with different folding speeds but the same chemical composition. By varying the UV light intensity during the photo‐crosslinking of the nanocomposite hydrogel, different types of microstructures can be realized via phase separation mechanisms, which allow to control the folding speeds. The self‐folding structures are fabricated by integrating two dissimilar materials (i.e., a nanocomposite hydrogel and an elastomer) into hinge‐based bilayer structures via extrusion‐based 3D printing. It has been demonstrated that the folding kinetics can be accelerated by more than one order of magnitude due to the phase‐separated microstructure formed by the relatively weaker UV intensity (≈10 mW cm‐2) compared to the one formed by stronger UV intensity (≈100 mW cm‐2). 3D structures with sequential self‐folding capabilities are realized by prescribing actuation speeds and folding angles to specific hinges of the nanocomposite hydrogel. Sequential folding box and self‐locking latch structures are fabricated to demonstrate the ability to capture and hold objects underwater.
Shape morphing of stimuli‐responsive composite hydrogels has received considerable attention in different research fields. Although various multilayer structures with dissimilar materials are studied to achieve shape morphing, combining swellable hydrogel layers with non‐swellable layers results in issues with interface adhesion and structural integrity. In this study, single‐hydrogel‐based bilayer actuators comprising poly(
- Award ID(s):
- NSF-PAR ID:
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Interfaces
- Medium: X
- Sponsoring Org:
- National Science Foundation
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