Self-recovery, fatigue and anti-fatigue of supramolecular elastomers

Supramolecular elastomers (SMEs) with chains bridged by covalent and non-covalent bonds demonstrate self-healing and self-recovery at room temperature. A model is developed for the kinetics of self-recovery in SME subjected to cyclic deformation. Good agreement is shown between results of simulation and observations on SMEs with metal-ligand coordination bonds, hydrogen bonds, ionic hydrogen bonds, and temporary junctions formed via inter-polymer complexation. Analysis of multi-cycle tests on SMEs reveals their anti-fatigue property (the ability to eliminate cyclic softening by introducing short intervals of recovery between subsequent cycles of deformation). Two scenarios for anti-fatigue are discussed. For SMEs with the exponential kinetics of recovery, the optimal duration of rest between cycles is close to the time needed for total self-recovery. When the recovery process involves two stages, less than 1 min of rest between cycles suffices to eliminate cyclic softening.