Shape-Memory Natural Rubber: An Exceptional Material for Strain and Energy Storage

Shape-memory polymers (SMPs) are smart, responsive materials with numerous potential applications. Based on previously introduced shape-memory natural rubber (SMNR), which shows exceptional properties such as strain storage of 1000%, cold storage, cold programmability, and mechanical and thermal triggers tunable both during and after programming, different SMNRs regarding their shape-memory parameters are investigated. Furthermore, their energy-storage capability and their mechanical properties are explored. SMNRs show fixity ratios of up to 94% and excellent recovery ratios of up to 100% whereas strains even above 1000% can be stored. Energies of up to 4.88 J g1 can be stored with efficiencies of up to 53.30%. Further, the Young's modulus of SMNR can be switched by two orders of magnitude upon triggering or programming.