“…86,183 Furthermore, the method renders a pathway to PBIs containing rotaxanes in the form of permethyl-β-cyclodextrin(s), 179 crown ethers, 184 furan, 35 organosilanes, 182 or ion exchange functionalities. 185,186 The method can also be used for alkylsulfonation employing e.g. 1,3-propane sultone, 187,188 1,4-butane sultone 189,190 or sodium (4-bromomethyl)benzenesulfonate 187,191 to give hydrophilic polyelectrolytes that become water soluble at high degrees of functionalization.…”