Optimization of Phase-Change Material-Elastomer Composite and Integration in Kirigami-Inspired Voxel-Based Actuators

Area of Science:

• Materials Science
• Robotics
• Soft Robotics

Background:

• Phase-change material-elastomer composite (PCMEC) actuators offer high energy density and actuation strain for soft robotics.
• Current limitations include high actuation temperatures, slow speeds, and a lack of standardized design approaches for complex tasks.
• Existing PCMEC actuators often use ethanol as the phase-change fluid, which can limit their application in sensitive environments.

Purpose of the Study:

• To develop a novel manufacturing approach for PCMEC actuators with diverse fluid-elastomer combinations.
• To investigate the impact of different phase-change fluids and elastomers on actuator performance (elongation, bending, speed, temperature).
• To propose a kirigami-inspired voxel-based design strategy for creating advanced soft robotic structures.

Main Methods:

• Developed a new manufacturing technique for PCMEC actuators, allowing for various fluid-elastomer pairings.
• Systematically evaluated the free elongation and bending characteristics of actuators with different internal fluids and elastomer matrices.
• Proposed and demonstrated a kirigami-inspired voxel design approach using reinforced PCMEC cubes for anisotropic deformation.

Main Results:

• Optimized fluid selection significantly improved actuation strain and speed while lowering actuation temperature compared to ethanol-based actuators.
• Actuator stiffness and curvature were tunable by selecting different elastomer materials, with curvature inversely proportional to the elastomer's Young's modulus.
• Demonstrated the potential for creating complex soft robotic behaviors (bending, torsion, elongation, compression, shear) using modular voxel designs.

Conclusions:

• The proposed manufacturing method enables the creation of tailored PCMEC actuators with enhanced performance characteristics.
• Optimized PCMEC actuators are suitable for applications requiring lower temperatures and faster responses, including close human contact.
• The voxel-based design approach facilitates the construction of reconfigurable and adaptable soft robots for complex tasks.