Extreme Energy-Absorbing Metamaterials Based on Liquid Crystal Elastomers

Liquid crystal elastomers (LCEs) are fascinating materials for energy dissipation, due to their extreme damping behavior emerging from an internal degree of freedom of LC molecules, which is coupled to elastic deformations of polymer network. Here, we report metamaterials composed of LCE beams for extreme energy absorption. We have synthesized LCEs through a two-stage thiol–acrylate reaction to consider the effects of the alignment of LC molecules within LCE beam elements. The energy-absorbing capability of metamaterials consisting of bistable beams with differently arranged LC molecules was characterized at strain rates from 10^-4/s to 10³/s and it followed a power-law relation. We observed that metamaterials based on LCE showed increase of the energy absorption at a higher strain rate. Moreover, the strain-rate dependency could be tuned by LCEs with different degree of alignment. We envision that our study can contribute to harnessing the interplay between snapping-based architectures and enhance dissipation of LCEs to enable the metamaterials with extreme energy-absorbing capabilities.