Mouldable liquid-crystalline elastomer actuators with exchangeable covalent bonds

Area of Science:

• Polymer Science
• Materials Science
• Soft Robotics

Background:

• Liquid-crystal elastomers (LCEs) offer potential for stimuli-responsive actuation.
• Macroscopic alignment of liquid-crystal order is crucial for reversible LCE actuation but difficult to achieve.
• Current LCE processing methods present significant practical limitations.

Purpose of the Study:

• To overcome the processing and alignment challenges in liquid-crystal elastomers.
• To develop a new class of processable and adaptable LCEs.
• To enable practical applications of LCEs in actuators and artificial muscles.

Main Methods:

• Introduction of exchangeable links into the polymer network, replacing permanent crosslinks.
• Utilizing vitrimer chemistry principles for polymer network modification.
• Investigating the processing, alignment, and mechanical relaxation behaviors of the new xLCEs.

Main Results:

• Successfully synthesized liquid-crystal elastomers with exchangeable links (xLCEs).
• Demonstrated that xLCEs are moldable, facilitating easier processing and alignment.
• Observed that xLCEs exhibit strong liquid-crystal alignment as a primary mechanism for mechanical relaxation, deviating from typical vitrimer behavior.

Conclusions:

• Exchangeable links provide a viable solution to the processing bottleneck in LCEs.
• xLCEs offer enhanced processability, alignment capabilities, and adaptability through remolding.
• The unique relaxation mechanism in xLCEs opens new avenues for designing advanced soft actuators and artificial muscles.