Thermal Gradient-Driven Heterogeneous Actuation of Liquid Crystal Elastomers for a Crawling Robot

Area of Science:

• Soft Robotics
• Materials Science
• Polymer Science

Background:

• Liquid crystal elastomers (LCEs) are advanced materials for soft robotics, offering large shape morphing for tasks like locomotion and camouflage.
• Current LCE soft robot actuation methods are often complex, requiring intricate designs, multi-material integration, or sophisticated programming.

Purpose of the Study:

• To develop a simple and efficient method for achieving multiple deformation modes in LCE-based soft robots.
• To explore the use of Joule heating via oxidized liquid metal (LM) films for controlled actuation of LCEs.

Main Methods:

• Utilized oxidized liquid metal (LM) thin films for Joule heating within LCE structures.
• Investigated the influence of actuation voltage, LCE dimensions, and LM-to-LCE thickness ratio on LCE deformation.
• Demonstrated coupled bending behaviors by actuating adjacent surfaces of an LCE strip.

Main Results:

• Achieved multiple deformation modes in a simply programmed LCE structure through controlled Joule heating and thermal gradients.
• Observed that LM films provide efficient heating, enhanced viscosity, high thermal conductivity, and deformability.
• Successfully demonstrated a crawling soft robot with multimode locomotion (forward movement, turns) using LM-coated LCE strips.

Conclusions:

• The proposed Joule heating strategy offers a straightforward and versatile approach for actuating LCE soft robots.
• This method enables precise control over deformation modes, enhancing biomimetic functionality.
• The technique shows significant potential for scalable applications in intelligent systems, soft robotics, and biomedical devices.