Poly-2-aminomethyl-3-(3,4-dihydroxyphenyl)propionamide: From Structure to Proprieties

The oxidative polymerization of the dopamine analogue, 2-aminomethyl-3-(3,4-dihydroxyphenyl)propionamide (DL), is presented and its polymerization product, PDL, is fully characterized both in bulk and as a coating layer on TiO2 and glass substrates. Standard oxidation conditions in 10 mM TrisCl aqueous solution at pH = 8.5 were employed for directly referencing the PDL characteristic features to those of polydopamine. These features were investigated by scanning electron microscopy (SEM)/ transmission electron microscopy (TEM), atomic force microscopy (AFM), DSC/TGA, MS-ESI(+), Zeta, ss-NMR, EPR, X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FT-IR), and ultraviolet-visible (UV-vis). Selective 13C and 15N isotopic labelling of the key chemical position in the DL side chain has facilitated the ss-NMR structural characterization of PDL and a better understanding of its polymerization mechanism. PDL shows fluorescence with a maximum 4% quantum yield when dissolved in methanol and better antibacterial effect compared to PDA, especially against Staphylococcus aureus.