3D Printing of Near-Ambient Responsive Liquid Crystal Elastomers with Enhanced Nematic Order and Pluralized Transformation

TL;DR

This paper introduces a hybrid cooling 3D printing method for liquid crystal elastomers that significantly enhances nematic order and enables complex shape morphing, advancing applications in soft robotics and biomedical devices.

Contribution

A novel hybrid cooling strategy for 3D printing NAT-LCEs that improves nematic order and allows intricate shape morphing with programmable properties.

Findings

Nematic order increased by 3000% compared to traditional methods.

Printed sheets exhibit spontaneous 3D shape transformation upon release.

Graded property NAT-LCEs enable complex shape morphing.

Abstract

Liquid Crystal Elastomers with near-ambient temperature-responsiveness (NAT-LCEs) have been extensively studied for building bio-compatible, low-power consumption devices and robotics. However, conventional manufacturing methods face limitations in programmability (e.g., molding) or low nematic order (e.g., DIW printing). Here, a hybrid cooling strategy is proposed for programmable 3D printing of NAT-LCEs with enhanced nematic order, intricate shape forming, and morphing capability. By integrating a low-temperature nozzle and a cooling platform into a 3D printer, the resulting temperature field synergistically facilitates mesogen alignment during extrusion and disruption-free UV cross-linking. This method achieves a nematic order 3000% higher than NAT-LCEs fabricated using traditional room temperature 3D printing. Enabled by shifting of transition temperature during hybrid cooling printing, printed sheets spontaneously turn into 3D structures after release from the platform, exhibiting bidirectional deformation with heating and cooling. By adjusting the nozzle and plate temperatures, NAT-LCEs with graded properties can be fabricated for intricate shape morphing. A wristband system with enhanced heart rate monitoring is also developed based on 3D-printed NAT-LCE. Our method may open new possibilities for soft robotics, biomedical devices, and wearable electronics.