Tunable Light-Responsive Polyurethane-urea Elastomer Driven by Photochemical and Photothermal Coupling Mechanism

Area of Science:

• Materials Science
• Robotics
• Biomedical Engineering

Background:

• Soft actuators mimic biological motion without rigid components.
• Existing photoresponsive materials lack desired mechanical, biological, and manufacturing properties for robotics.

Purpose of the Study:

• To synthesize and characterize a novel visible-light-responsive thermoplastic elastomer for soft robotics and biomedical applications.
• To demonstrate the material's potential in light-driven actuators with tunable mechanical properties.

Main Methods:

• Synthesized a polyurethane urea elastomer (PAzo) incorporating azobenzene derivatives.
• Fabricated bilayer actuators using PAzo and polyimide films.
• Investigated actuation mechanisms through experimental and theoretical analyses.

Main Results:

• PAzo elastomer exhibits light-driven stiffness softening and excellent hyperelasticity (575.2% stretchability, 17.6 MPa modulus, 44.0 MPa strength).
• Tunable bending modes achieved in bilayer actuators by varying light intensity.
• Demonstrated a visible-light-controlled soft robotic finger application.

Conclusions:

• The robust, biocompatible, and scalable PAzo elastomer is suitable for light-driven actuators.
• This material advances the development of wearable/implantable devices and soft robots for clinical use.