Thermal‐Induced Transformation of Polydopamine Structures: An Efficient Route for the Stabilization of the Polydopamine Surfaces

This work brings a new insight into the structural transformation and stabilization of polydopamine (PDA) surfaces induced by thermal treatment. Taking advantage of the isotopic enrichment, 15 N CP/MAS NMR experiments produce significant signal enhancements for PDA, allowing detection of a range of nitrogen structural units—the reaction products of the conversion of NH 3 + units of 15 N‐dopamine·HCl. In addition, 1 H‐ 15 N cross‐polarization polarization‐inversion profiles measured for each of the detected 15 N NMR signals and 1 H‐ 15 N FSLG HETCOR NMR spectra allow revisions and extensions to be made in a structural elucidation of PDA. Combining the NMR data thermogravimetric analyses and an FTIR analysis, several competitive processes that occur during the thermal conversion of dopamine are identified.