Tailoring Diels-Alder Cross-Linked Liquid Crystal Elastomers for Spatially Programmable Monolithic Actuators

Area of Science:

• Materials Science
• Polymer Chemistry
• Soft Robotics

Background:

• Liquid crystal elastomers (LCEs) with thermo-reversible Diels-Alder cross-links (DALCEs) offer reprocessability and reprogrammability for actuator fabrication.
• Optimizing molecular design and refabrication protocols is key to maximizing DALCE potential.

Purpose of the Study:

• To systematically investigate DALCEs synthesized via aza-Michael addition.
• To examine the effects of cross-linking density and chain extender selection on material properties and actuation performance.
• To introduce a novel fabrication strategy for spatially programmable, dynamic monolithic actuators.

Main Methods:

• Synthesis of DALCEs using RM82, furfurylamine, and various chain extenders.
• Characterization of phase behavior, thermomechanical properties, and actuation performance.
• Development and application of a multilevel fiber programming and monolithic actuator formation strategy.

Main Results:

• A PEA-based formulation with moderate cross-linking density demonstrated balanced performance.
• The novel fabrication strategy successfully enabled spatially controlled liquid crystal alignment.
• Demonstrated complex morphing behaviors in disk films and stress-modulating functions in tubular actuators.

Conclusions:

• Established a versatile and easily synthesized material platform for programmable, dynamic monolithic actuators.
• The developed strategy leverages DALCEs' reprocessability, reprogrammability, and self-healing properties.
• Paved the way for advanced applications in soft robotics and adaptive devices.