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Updated: Jul 4, 2026
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An Additive Manufacturing Technique for the Facile and Rapid Fabrication of Hydrogel-based Micromachines with Magnetically Responsive Components
Published on: July 18, 2018
Unparalleled nanofibril hydrogel actuators by mimicking nature's design
Farhiya Alex Sellman1,2, Rebecca Östmans1,2, Tobias Benselfelt1,2
1Department of Fibre and Polymer Technology, KTH Royal Institute of Technology Stockholm 11428 Sweden fase@kth.se bense@kth.se.
RSC Advances
|July 3, 2026
Summary
Anisotropic cellulose nanofibril (CNF) hydrogels offer a breakthrough for soft actuators, achieving rapid, high-force, and large-strain actuation by controlling water uptake. These engineered hydrogels pave the way for advanced artificial muscles.
Area of Science:
- Materials Science
- Biomimetics
- Soft Robotics
Background:
- Soft actuators mimic natural muscles using stimuli-responsive hydrogels.
- Current hydrogel actuators face limitations in response speed and force due to diffusion-limited water transport and uniform swelling.
- A need exists for faster hydrogel actuators with efficient conversion of swelling into actuation force and strain.
Purpose of the Study:
- To investigate how the structure and processing of charged cellulose nanofibril (CNF) networks govern swelling-driven actuation.
- To optimize CNF hydrogel properties for enhanced actuation performance, including speed, force, and strain.
- To demonstrate the potential of anisotropic CNF hydrogels as a platform for high-performance artificial muscles.
Main Methods:
- Fabrication of anisotropic cellulose nanofibril (CNF) hydrogels with controlled fibril properties (aspect ratio, charge density) and sheet parameters (drying conditions, actuator area).
- Characterization of swelling-driven actuation, including uniaxial expansion, strain rates, and blocking pressures.
- Analysis of the relationship between CNF network structure, processing parameters, and actuation output.
Main Results:
- Optimized CNF networks exhibited uniaxial expansion up to 220 times within an hour.
- Achieved rapid initial strain rates of 190-300% s-1.
- Reached high blocking pressures up to 4.9 MPa in under a minute, demonstrating efficient force generation.
Conclusions:
- Anisotropic CNF hydrogels overcome the limitations of conventional hydrogel actuators by redirecting water uptake for directional expansion and high blocking pressure.
- The developed CNF hydrogels offer a significant advancement towards hydrogel-based artificial muscles, addressing the critical issue of slow response times.
- Further development of these fibrillar hydrogel actuators holds promise for creating lifelike, high-performance artificial muscles.
