Tunable Energy Absorption Characteristics of 3D-Printed Anisotropic Liquid Crystal Elastomers

The rotation of liquid crystal mesogens consumes energy, making liquid crystal elastomers (LCE) a promising soft material for energy absorption. Compared to various fabrication techniques, three-dimensional (3D) printing provides significant advantages in customizing the anisotropy and tuning energy absorption properties of LCE. However, the connection between printing parameters and the energy absorption of printed anisotropic LCEs remains unclear in the literature. In this study, we explore the mechanical and energy absorption properties of 3D-printed LCE samples as influenced by key printing parameters, including the filament angle, the pattern of printed substructure, and the infill density. Our findings indicate that polydomain LCEs exhibit isotropic mechanical properties and are largely unaffected by filament angles. In contrast, for monodomain LCEs, a reduction in filament angle and an increase in infill density both enhance energy absorption. Furthermore, we demonstrate that the adhesive strength between printed filaments is not a weak point, as it closely matches the cohesive strength in both polydomain and monodomain LCEs. Additionally, the energy absorption rate of 3D-printed LCE films under impact loading is significantly higher than that of traditional rubber films. These insights provide valuable guidance for the application of 3D-printed LCE-based soft machines in energy absorption contexts.