“…Despite their outstanding separation performance, PIM-1 membranes undergo physical aging, a reversible polymer chain rearrangement due to the relaxation of the non-equilibrium polymeric chains, which implies the loss of free volume (increase chain packing) and the decay of the permeability over time, this fact being the main constraint for their industrial application [26]. In this sense, great efforts have been expended to minimize or avoid the aging phenomenon of PIM membranes by techniques such as the incorporation of inorganic fillers to the PIM-1 matrix [21,27,28]. Moreover, the topology of the PIM-1 also influences both the separation properties and the rate of physical aging [29,30].…”