Digital light processing of liquid crystal elastomers for self-sensing artificial muscles

Area of Science:

• Materials Science
• Robotics
• Polymer Chemistry

Background:

• Stimuli-responsive polymers offer advantages like mechanical compliance and high power-to-weight ratios for artificial muscles.
• Liquid crystal elastomers (LCEs) are promising thermomechanical actuators for soft robotics, wearable electronics, and biomedical devices due to their large stroke, fast response, and repeatability.

Purpose of the Study:

• To introduce a digital light processing (DLP)-based additive manufacturing method for creating highly ordered liquid crystal elastomers (LCEs).
• To demonstrate the application of these DLP-printed LCE actuators in soft robotics and develop an LCE self-sensing system.

Main Methods:

• Utilized digital light processing (DLP) 3D printing to shear align mesogenic oligomers layer-by-layer.
• Fabricated photocrosslinked structures with high orientational order.
• Developed LCE actuators and a self-sensing system leveraging thermally induced optical transitions.

Main Results:

• Achieved high orientational order in photocrosslinked LCE structures through automated shear alignment.
• Demonstrated high specific work capacity (63 J kg^-1) and energy density (0.18 MJ m^-3).
• Showcased applications in soft robotics, including reversible grasping, untethered crawling, and weightlifting.

Conclusions:

• DLP-based additive manufacturing enables the creation of high-performance artificial muscles from LCEs.
• The developed LCE actuators are suitable for advanced soft robotic applications.
• An intrinsic self-sensing capability was demonstrated for feedback control in LCE systems.