Swelling and deswelling driven multimaterials silicone hopper with superior specific power and energy

• Published in: Materials & design Vol. 241; p. 112960
• Main Authors: Hu, Sizi, Li, Chengzhi, Wang, Haochen, Mylo, Max D., Becker, Jing, Cao, Bo, Müller, Claas, Eberl, Christoph, Yin, Kaiyang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2024; Elsevier
• Subjects: Bioinspired; Porous materials; Power amplification; Snap-through; Soft robotics; Soft robotics; Bioinspired; Power amplification; Porous materials; Snap-through
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2024.112960

[Display omitted] •Single- and multimaterials silicone disks showed inhomogeneous swelling and deswelling driven, snap-through jump, demonstrating potentials in programmable environment responsive actuation for soft robotics.•The optimized combination of materials and their distribution led to a jump height of 321 mm, specific power of 1782 W kg−1, and specific energy of 4.44 J kg-1.•The bioinspired materials selection and geometry with a stiff confinement and an elastic snap-through part improved the energy output, widely applicable for systems with similar underlying processes.•Illustrated quantitatively the influence of porous materials on mass transport and strain evolution during deswelling, providing a powerful way to further custom design. Bioinspired, bistable snap-through structures are promising to release a burst of mechanical energy transformed from chemical energy, stored, and released incrementally during swelling/deswelling. Thin, disk-like hopper can harness the inhomogeneous deswelling to create the required constraint and flexible snap-through part. Here, hoppers composed of a single type of polydimethylsiloxane (PDMS) or concentric PDMS rimmed by a stiffer PDMS are cast into precisely micromachined molds. The mechanical properties and swelling/deswelling behavior of the constraining rim and flexible snap-through materials, in concert, allow a superior specific power of 1782 W kg−1, specific energy of 4.44 J kg−1 for a jump up to 321 mm, outperforming many more complex implementations. The jump benefits from an improved storage modulus ratio and a lower swell of the rim to the snap-through center part, which enhanced the confinement and elastic energy storage. A sharp spatial gradient in volume change between the two materials during deswelling, tunable by the porosity of the rim materials, enhances the jumping by allowing more material to store and release elastic energy, revealed by the strain analysis with 3D-digital image correlation. The illustrated multimaterials and porous materials strategies can promote the development of integrated energy harvesting and actuation for soft robotics.