The chemical structure of the PIPA-coated supports and the mLbL-assembled membranes (x = 15) was characterized by FT-IR as shown in Fig. 6. Both PIPA-coated supports showed Topotecan HCl characteristic FT-IR peak at 1625 cm−1 (CO stretching, amide I of the semi-aromatic PA) . Upon mLbL deposition, a small peak became evident at 1541 cm−1 (N–H in-plane bending, amide II of the fully-aromatic PA) with the peak at 1625 cm−1 being more pronounced by overlapping of the peak at 1610 cm−1 (H-bonded CO stretching of the fully-aromatic PA) due to the formation of a cross-linked aromatic PA layer via mLbL on top of the PIPA interlayer. It should be noted oxytocin the PAN(PIPA0.5)[MPD/TMC]15 exhibited more intensified peaks at 1625 cm−1 and 1541 cm−1 with a prominent shoulder at 1671 cm−1 (CO stretching, amide I of the fully-aromatic PA) compared to the PAN(PIPA0.05)[MPD/TMC]15. This result indicates that more and denser PA layer was grown on the PIPA0.5 interlayer, which is consistent with the above performance result.