Fuel-Driven Redox Reactions in Electrolyte-Free Polymer Actuators for Soft Robotics.

Area of Science:

• Materials Science
• Polymer Chemistry
• Robotics

Background:

• Shape-changing polymers are key for artificial muscles and soft robotics.
• Existing polymer actuators face challenges due to extreme actuation conditions.
• New stimuli are needed to expand the applications of polymer artificial muscles.

Purpose of the Study:

• To introduce a novel all-solid fuel-powered actuator.
• To demonstrate its potential for biomimetic artificial muscles and soft robotics.
• To overcome limitations of current polymer actuators.

Main Methods:

• Developed a fuel-powered actuator utilizing hydrogen (H2) and oxygen (O2) redox reactions.
• Characterized actuation magnitude, work capacity, and reversibility.
• Embedded actuators in a soft humanoid hand to demonstrate functionality.

Main Results:

• Achieved a reversible actuation magnitude of up to 3.8% and a work capacity of 120 J/kg.
• Demonstrated athermal actuation without electrolytes, electrodes, or external voltage.
• Actuator maintained position under load without energy consumption (catch state).
• Outperformed reported polymer redox actuators in stress-free contraction strain and blocking stress.

Conclusions:

• The fuel-powered actuator offers a promising alternative to existing artificial muscles.
• Eliminates need for electrolytes, electrodes, and external voltage, simplifying applications.
• Opens new possibilities for redox polymers in soft robotics and artificial muscle technologies.