Humidity-responsive fiber actuators assembled from cellulose nanofibrils

Area of Science:

• Materials Science
• Robotics
• Nanotechnology

Background:

• Fiber actuators are crucial for soft robotics and environmental sensing.
• Existing biofiber actuators offer cost-effectiveness and biodegradability but have limitations.
• A gap exists in developing advanced functional systems using these materials.

Purpose of the Study:

• To develop novel moisture-responsive fiber actuators from cellulose nanofibrils (CNFs).
• To create both torsional and tensile actuators with enhanced functionality.
• To showcase the potential of CNFs in next-generation smart materials.

Main Methods:

• Fabrication of CNF filaments via wet-spinning.
• Twisting CNF filaments to create a torsional actuator.
• Integrating a supercoiled nylon fiber core within a CNF sheath for a tensile actuator.

Main Results:

• The torsional actuator exhibited rapid rotational response (up to 1180 rpm in 10 s) upon moisture exposure.
• The CNF filaments demonstrated high mechanical strength (237.0 ± 10.7 MPa) and durability.
• The developed tensile actuator design enhanced structural support and functionality.

Conclusions:

• Cellulose nanofibrils (CNFs) are versatile for creating advanced moisture-responsive actuators.
• The developed actuators demonstrate significant potential for soft robotics and environmental sensing applications.
• This work represents an iterative advancement in actuator technology using sustainable materials.