3D Printing of Liquid Crystal Elastomeric Actuators with Spatially Programed Nematic Order

TLDR

Liquid crystal elastomers are soft materials that can undergo large, reversible shape changes, making them promising for artificial muscles, soft robots, and dynamic functional architectures. This study reports the design and additive manufacturing of LCE actuators with spatially programmed nematic order that achieve large, reversible, repeatable contraction and high specific work capacity. The authors develop a photopolymerizable, solvent‑free main‑chain LCE ink via aza‑Michael addition and employ high‑temperature direct‑ink writing to align mesogen domains along the print path. The resulting shape‑morphing LCEA architectures exhibit reversible planar‑to‑3D and 3D‑to‑3D′ transformations on demand and can lift significantly more weight than previously reported LCEAs.

Abstract

Liquid crystal elastomers (LCEs) are soft materials capable of large, reversible shape changes, which may find potential application as artificial muscles, soft robots, and dynamic functional architectures. Here, the design and additive manufacturing of LCE actuators (LCEAs) with spatially programed nematic order that exhibit large, reversible, and repeatable contraction with high specific work capacity are reported. First, a photopolymerizable, solvent-free, main-chain LCE ink is created via aza-Michael addition with the appropriate viscoelastic properties for 3D printing. Next, high operating temperature direct ink writing of LCE inks is used to align their mesogen domains along the direction of the print path. To demonstrate the power of this additive manufacturing approach, shape-morphing LCEA architectures are fabricated, which undergo reversible planar-to-3D and 3D-to-3D' transformations on demand, that can lift significantly more weight than other LCEAs reported to date.