We show that the inclusion of ZIF-8 nanoparticles into Matrimid controls many important mechanical behaviour, ranging from elastic modulus, yield strength and hardness, to ductility, fracture strength and toughness. We identified that annealing (180 °C), despite improving the gas permeability and selectivity of Matrimid-based membranes, could substantially degrade its ductility and fracture toughness, while stabilising small-strain viscoelastic response under dynamic loading. Our results suggest that an annealed <~10 wt% ZIF-8/Matrimid MMM would be ideal for practical separation applications, where an optimal combination of mechanical resilience in conjunction with excellent gas permselectivity are the prerequisites.
