An Anionic Framework-Enabled Ion-Anchoring Strategy for Frequency-Tolerant Electrochemical Actuation.

Area of Science:

• Materials Science
• Robotics
• Electrochemistry

Background:

• Artificial muscles offer potential for bionic robotics due to their biomimetic properties.
• Existing ionic electrochemical actuators suffer from frequency dependence and unstable outputs, limiting their applications.

Purpose of the Study:

• To develop an artificial muscle with stable actuation performance across a broad frequency range.
• To investigate the mechanism behind stable actuation in ionic electrochemical actuators.

Main Methods:

• Fabrication of a novel electrolyte membrane using zinc tetraphenylporphyrin (Zn-TPP) and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4).
• Characterization of actuator performance, including displacement retention and stability under variable frequencies and humidity.
• Comparison with conventional EMImBF4/PVDF-HFP based actuators.

Main Results:

• The Zn-TPP/EMImBF4 electrolyte membrane actuator achieved 99.97% displacement retention from 0.1-5 Hz at 3 V.
• A positive correlation was found between the electrostatic potential of TPP2- and actuator displacement retention.
• The actuator demonstrated stable performance in a relative humidity range of 40-70% and mimicked human Achilles tendon contraction.

Conclusions:

• The developed artificial muscle overcomes frequency dependence issues in ionic electrochemical actuators.
• The anchoring effect of the TPP2- framework stabilizes cation migration, leading to consistent performance.
• This technology offers a tunable balance between stability and displacement amplitude for next-generation soft robotics.