“…The key problem with most of the demonstrated PILs is that they are mechanically weak and thus could not be used as membranes at higher pressure [6,14,15]. To conquer this issue, various methodologies, such as crosslinking [15][16][17][18][19][20], copolymerization [14,21,22], polymerization of IL-monomers on porous polymer support [15,17,20,23,24] and recently, PILs based on N-quaternization of fully aromatic polybenzimidazole (PBI) backbone [25][26][27] are being explored.…”