Fig. 2: Morphology and elemental characterisations of zwitterion-grafted polyurethanes and controls using SEM, AFM, and XPS.
From: Durable plasma-mediated zwitterionic grafting on polymeric surfaces for implantable medical devices
a–f Morphological analysis. The surface morphology of a PU, b C-PU, c PIII-PU, and d ZG-PU was imaged using SEM, demonstrating a distinct morphology formed due to PIII-mediated zwitterion grafting. These observations were validated by AFM via 3D reconstruction of the surface morphologies of e C-PU and f ZG-PU. g–k Elemental analysis. g XPS survey spectra for all groups, with peaks at O1s, N1s, C1s, S1s and S2p used to calculate elemental compositions. h Detailed analysis of the N1s spectrum demonstrated a significant and shifted peak for ZG-PU, while i detailed analysis of the S2p spectra also demonstrated a significant peak for ZG-PU. Deconvolution of the j N1s and k S2p spectra further indicated the presence of SBMA in ZG-PU by the identification of an N1s peak associated with the SBMA quaternary ammonium cation, and distinct orbital splitting in the S2p peak.
