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arXiv · 2303.13878

Overcoming water diffusion limitations in hydrogels via microtubular graphene networks for soft actuators

Margarethe Hauck·Lena M. Saure·Berit Zeller-Plumhoff·Sören Kaps·Jörg Hammel·Caprice Mohr·Lena Rieck·Ali Shaygan Nia·Xinliang Feng·Nicola M. Pugno·Rainer Adelung·Fabian Schütt
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Abstract

Hydrogel-based soft actuators can operate in sensitive environments, bridging the gap of rigid machines interacting with soft matter. However, while stimuli-responsive hydrogels can undergo extreme reversible volume changes of up to ~90%, water transport in hydrogel actuators is in general limited by their poroelastic behavior. For poly(N-isopropylacrylamide) (PNIPAM) the actuation performance is even further compromised by the formation of a dense skin layer. Here we show, that incorporating a bioinspired microtube graphene network into a PNIPAM matrix with a total porosity of only 5.4 % dramatically enhances actuation dynamics by up to ~400 % and actuation stress by ~4000 % without sacrificing the mechanical stability, overcoming the water transport limitations. The graphene network provides both untethered light-controlled and electrically-powered actuation. We anticipate that the concept provides a versatile platform for enhancing the functionality of soft matter by combining responsive and two-dimensional materials, paving the way towards designing soft intelligent matter.

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Margarethe Hauck, Lena M. Saure, Berit Zeller-Plumhoff, Sören Kaps, Jörg Hammel, Caprice Mohr, Lena Rieck, Ali Shaygan Nia, Xinliang Feng, Nicola M. Pugno, Rainer Adelung, Fabian Schütt. 2023-03-24. Overcoming water diffusion limitations in hydrogels via microtubular graphene networks for soft actuators. https://doi.org/10.1002/adma.202302816

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