Readily Programmable, Body Temperature-Responsive Liquid Crystal Elastomers With Dynamic Covalent Thiourea Bonds

Area of Science:

• Materials Science
• Polymer Chemistry
• Soft Robotics

Background:

• Liquid crystal elastomers (LCEs) are stimuli-responsive materials with thermotropic shape-changing properties.
• Conventional LCEs have high transition temperatures (>60°C), limiting their use in human-interfacing applications.
• There is a need for LCEs that can actuate at body temperature for biomedical and wearable applications.

Purpose of the Study:

• To develop body heat-responsive LCEs.
• To incorporate dynamic thiourea bonds for reprocessability and ambient temperature reprogrammability.
• To investigate the effect of comonomer structure on actuation performance and network malleability.

Main Methods:

• Synthesized LCEs with dynamic thiourea bonds and specific comonomers.
• Performed systematic formulation studies to optimize LCE properties.
• Evaluated actuation performance, network malleability, and reprogrammability at various temperatures.
• Fabricated and tested a bump-array actuator demonstrating reversible surface topography changes.

Main Results:

• Developed LCEs that actuate effectively at body temperature (below 60°C).
• Incorporated dynamic thiourea bonds, enabling reprocessability and ambient temperature reprogrammability.
• Demonstrated that comonomer structure significantly influences actuation performance and malleability.
• Showcased a functional bump-array actuator with reversible body-heat-induced topography changes.

Conclusions:

• Body heat-responsive LCEs with dynamic thiourea bonds offer a promising platform for human-interfacing applications.
• The developed LCEs exhibit excellent reprocessability and reprogrammability, facilitating complex structure fabrication.
• These materials pave the way for advanced soft robotics, wearable devices, and biomedical applications requiring precise thermal actuation.