Key Takeaways & Executive Findings
- •• • Achieved a maximum contractile stroke of 16% at a low voltage range of −1 to 1.8 V, demonstrating high actuation performance suitable for low-power biomedical and robotic applications. • • Generated an isometric force of approximately 500 mN at −1 to 2 V, enabling robust mechanical output for actuation tasks requiring significant force generation. • • The all-solid-state design eliminates liquid electrolyte leakage risks and improves biocompatibility, addressing critical safety and encapsulation challenges in implantable and wearable devices. • • The muscle unit retained structural integrity and actuation performance after weaving and knotting, indicating excellent mechanical robustness and flexibility for integration into complex textile-based systems.
Abstract
Conventional electrochemical artificial muscles rely on liquid electrolytes, which suffer from poor encapsulation processability, high leakage risks, and inadequate biocompatibility, limiting their application in bionic medicine, wearable exoskeletons, and humanoid robots. To address these bottlenecks, we fabricated a polyvinyl alcohol-polyacrylic acid (PVA-PAA) double-network hydrogel electrolyte and integrated it with twisted carbon nanotube (CNT) yarns via ultraviolet curing, constructing an all-solid-state artificial muscle unit. The unit maintained structural integrity and actuation performance after mechanical deformation treatments such as weaving and knotting. Experimentally, it achieved a maximum contractile stroke of 16% at −1 to 1.8 V and generated an isometric force of approximately 500 mN at −1 to 2 V. The solid-state artificial muscles exhibited excellent mechanical properties, compact size, and high flexibility, offering new opportunities for applications in bionic medical devices and intelligent robots.
1. Introduction
Conventional electrochemical artificial muscles rely on liquid electrolytes, which present significant barriers to practical deployment: poor encapsulation processability, high leakage risks, and inadequate biocompatibility. These drawbacks severely restrict their use in advanced domains such as bionic medicine, wearable exoskeletons, and humanoid robots, where safety, durability, and seamless integration are paramount. The need for solid-state electrolytes with high ionic conductivity and biocompatibility is therefore urgent to advance the field.
This work addresses this bottleneck by fabricating a polyvinyl alcohol-polyacrylic acid (PVA-PAA) double-network hydrogel electrolyte and integrating it with twisted carbon nanotube yarns via ultraviolet curing. The resulting all-solid-state artificial muscle unit achieves a maximum contractile stroke of 16% at −1 to 1.8 V and an isometric force of approximately 500 mN at −1 to 2 V, while maintaining structural integrity after mechanical deformation. This approach offers a viable pathway to high-performance, flexible, and safe artificial muscles for next-generation intelligent systems.
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DENG Bingbing, WANG Xiaobo, WANG Jiaqi, WANG Xiaona, DI Jiangtao (2026). High-Performance All-Solid-State Artificial Muscles Enabled by Double-Network Hydrogel Electrolytes. SCIENCE CHINA Materials. https://doi.org/10.1007/s40843-026-4298-x
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Frequently Asked Questions
What is the maximum contractile stroke and at what voltage range is it achieved?
The maximum contractile stroke is 16%, achieved at a voltage range of −1 to 1.8 V.
What isometric force can the artificial muscle generate and under what conditions?
The artificial muscle generates an isometric force of approximately 500 mN at a voltage range of −1 to 2 V.
How does the all-solid-state design address the limitations of liquid electrolytes?
The all-solid-state design eliminates leakage risks and improves biocompatibility, while maintaining high ionic conductivity, thus overcoming key barriers to practical application in biomedical and wearable devices.
What mechanical deformation treatments can the muscle unit withstand without significant performance loss?
The muscle unit can undergo weaving and knotting while maintaining structural integrity and actuation performance, demonstrating excellent mechanical robustness and flexibility.
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