“…The TFN membranes show characteristic peaks of PVA appearing at 2940 cm À1 , 2910 cm À1 , 1430 cm À1 , and 1095 cm À1 , which corresponds to CH 2 asymmetric stretching, CH 2 symmetric stretching, CH 2 in-plane scissoring, and CAO stretching vibrations, respectively [18]. The distinct broad band at 3000-3600 cm À1 is due to the stretching vibration of OH groups in the PVA polymer chain and from pendent aldehyde groups from incomplete cross-linking reactions [13,14]. This band intensified as the concentration of aluminosilicate single-walled nanotubes in the PVA matrix increased due to the OH stretching of the hydroxyl groups present in the imogolite [18].…”