Stiffness-gradient adhesive structure with mushroom-shaped morphology via electrically activated one-step growth

Area of Science:

• Biomimetics and Materials Science
• Robotics and Adhesion Technology

Background:

• Reptilian adhesion systems showcase remarkable adaptation to diverse environments.
• Stiffness gradient structures in nature enhance adhesion adaptation and stability.
• Replicating these complex gradient structures for bioinspired adhesives presents engineering challenges.

Purpose of the Study:

• To develop a bioinspired dry adhesive with a stiffness gradient structure.
• To overcome limitations in replicating natural adhesion morphologies and composite properties.
• To enhance the performance of dry adhesives for practical applications.

Main Methods:

• Electrically activated one-step growth process to create mushroom-shaped structures.
• Rheological growth under an electric field for structural morphology.
• Dielectrophoresis of nanoparticles to achieve a rigid-top, soft-bottom stiffness gradient.

Main Results:

• Achieved a stiffness gradient adhesive structure with mushroom-shaped morphology.
• Demonstrated significant improvements in adhesion strength: 3x in parallel and 5x in non-parallel states compared to homogeneous structures.
• Successfully applied the adhesive structures in wall-climbing robots.

Conclusions:

• The proposed stiffness gradient structure effectively mimics natural reptilian adhesion.
• This bioinspired adhesive offers superior adhesion performance and adaptability.
• Opens new possibilities for advanced dry adhesive-based devices and robotic systems.