Robotic Materials

Electrochemically Controlled Hydrogels with Electrotunable Permeability and Uniaxial Actuation

2023

Article

rm

The unique properties of hydrogels enable the design of life-like soft intelligent systems. However, stimuli-responsive hydrogels still suffer from limited actuation control. Direct electronic control of electronically conductive hydrogels can solve this challenge and allow direct integration with modern electronic systems. An electrochemically controlled nanowire composite hydrogel with high in-plane conductivity that stimulates a uniaxial electrochemical osmotic expansion is demonstrated. This materials system allows precisely controlled shape-morphing at only −1 V, where capacitive charging of the hydrogel bulk leads to a large uniaxial expansion of up to 300%, caused by the ingress of ≈700 water molecules per electron–ion pair. The material retains its state when turned off, which is ideal for electrotunable membranes as the inherent coupling between the expansion and mesoporosity enables electronic control of permeability for adaptive separation, fractionation, and distribution. Used as electrochemical osmotic hydrogel actuators, they achieve an electroactive pressure of up to 0.7 MPa (1.4 MPa vs dry) and a work density of ≈150 kJ m−3 (2 MJ m−3 vs dry). This new materials system paves the way to integrate actuation, sensing, and controlled permeation into advanced soft intelligent systems.

Author(s): Tobias Benselfelt and Jyoti Shakya and Philipp Rothemund and Stefan B Lindström and Andrew Piper and Thomas E Winkler and Alireza Hajian and Lars Wågberg and Christoph Keplinger and Mahiar Max Hamedi
Journal: Advanced Materials
Volume: 35
Number (issue): 45
Pages: 2303255
Year: 2023
Month: November
Publisher: Wiley-VCH GmbH
Department(s): Robotic Materials
Bibtex Type: Article (article)
Paper Type: Journal
DOI: doi.org/10.1002/adma.202303255
URL: https://onlinelibrary.wiley.com/doi/full/10.1002/adma.202303255

BibTex 

@article{Keplinger23-AM-Hydrogels,
  title = {Electrochemically Controlled Hydrogels with Electrotunable Permeability and Uniaxial Actuation},
  author = {Benselfelt, Tobias and Shakya, Jyoti and Rothemund, Philipp and Lindstr{\"o}m, Stefan B and Piper, Andrew and Winkler, Thomas E and Hajian, Alireza and Wågberg, Lars and Keplinger, Christoph and Hamedi, Mahiar Max},
  journal = {Advanced Materials},
  volume = {35},
  number = {45},
  pages = {2303255},
  publisher = {Wiley-VCH GmbH},
  month = nov,
  year = {2023},
  doi = {doi.org/10.1002/adma.202303255},
  url = {https://onlinelibrary.wiley.com/doi/full/10.1002/adma.202303255},
  month_numeric = {11}
}