Figure 11: SEM photographs of HTCC/QPVA membranes (a) without crosslinking (b) cross-linked by GA with an amount of 0.6/2.2 mmol mmol-1 (c) crosslinked by EGDGE with an amount of 0.6/2.2 mmol mmol-1 and (d) cross-linked by GA/EGDGE with an amount of each 0.6/2.2 mmol mmol-1.