Origami Metamaterials Enable Low-Stress-Driven Giant Elastocaloric Effect

Abstract

Elastocaloric materials, capable of achieving reversible thermal changes in response to a uniaxial stress, have attracted considerable attention for applications in advanced thermal management technologies, owing to their environmental friendliness and economic benefits. However, most elastocaloric materials operating on the basis of first/ second-order phase transition often exhibit a limited caloric response, field hysteresis, and restricted working temperature ranges. This study resorts to origami engineering for realizing multifunctional metamaterials with exceptional elastocaloric effects at both nano (exemplified by computational simulations for graphene) and meso (demonstrated by experimentation on thermoplastic polyurethane elastomers) scales. The findings uncover that the graphene origami exhibits low-stress-driven reversible and giant elastocaloric effects without a hysteresis loss and with a high elastocaloric strength. These effects are achieved across a wide working temperature range (100−600 K) and are tailorable by fine-tuning the topological parameters and configurational status of the origami metamaterials. We demonstrate the scalability of the origami design strategy for magnifying the elastocaloric effect by the 3D printing of a mesoscale origami-inspired thermoplastic polyurethane metastructure that showcases enhanced elastocaloric performance at room temperature. This study presents the potential for the realization of architected elastocaloric materials through surface functionalization and origami engineering. The findings impart exciting prospects of elastocaloric origami metamaterials as the next generation of multiscale and sustainable thermal management technologies.

Enhanced Elastocaloric Effects in γ-Graphyne

“…While computational studies on the eC effect in nanomaterials are still in their early stages, noteworthy findings have already been obtained. − Lisenkov et al pioneered molecular dynamics-based predictions for eC effects in graphene and carbon nanotubes. Similarly, Zhang explored eC effects in boron-nitride nanotubes, and Patel and Kumar predicted the eC effect in zinc-oxide nanowires.…”

“…A similar method was applied to unveil eC behaviors in graphene kirigami . Utilizing different protocols, Zhao, Guo, and Zhang and Cai, Yang, and Akbarzadeh predicted significant COP in 3D graphene architectures and graphene origami, respectively. However, to our knowledge, the eC effect in graphyne-based structures remains to be fully explored.…”