Electroosmosis-Driven Hydrogel Actuators Using Hydrophobic/Hydrophilic Layer-By-Layer Assembly-Induced Crack...

Area of Science:

• Materials Science
• Robotics
• Chemical Engineering

Background:

• High-performance soft actuators are crucial for advancing soft applications.
• Electrochemical actuators offer advantages like low-voltage control but are limited by conventional electrode expansion.
• Existing actuator technologies have not met the demand for superior performance and controllability.

Purpose of the Study:

• To develop a novel hydrogel actuator with enhanced performance and versatile controllability.
• To overcome the limitations of traditional electrochemical actuators.
• To explore a new actuation mechanism based on electroosmotic pumping.

Main Methods:

• Fabrication of cracked electrodes with interconnected metal nanoparticles on hydrogels via layer-by-layer assembly.
• Utilizing amphiphilic interaction-induced layer-by-layer assembly and nanoparticle shape transformation.
• Employing electroosmotic pumping to induce rapid and substantial hydrogel swelling.

Main Results:

• Achieved an actuation strain exceeding 20% and an energy density of 1.06 × 10^5 J m^-3.
• Demonstrated actuation in various geometries (curved-planar, square-pillared) and motions (slow-relaxation, spring-out, 2-DOF bending).
• Reported a 10-fold improvement in energy density compared to skeletal muscle, electrochemical actuators, and other hydrogel actuators.

Conclusions:

• The electroosmosis-driven hydrogel actuator offers a significant leap in performance for soft actuation.
• The monolithic structure and novel actuation mechanism enable versatile and powerful soft robotic movements.
• This technology paves the way for next-generation soft actuators with unprecedented energy density and control.