An alternative method for anodic electropolymerization of polymelamine in water-free deep eutectic solvents

In our previous study (Electrocatalysis 15: 394–400, 2024), we proposed a method for preparing polymelamine (pMel) by adding a small amount of water to deep eutectic solvents (DES). However, electropolymerization under completely anhydrous conditions has not yet been achieved. This study experimentally identified that the main challenges in electropolymerizing melamine in anhydrous DES solutions are the low concentration of melamine monomer used in current literature and the slow diffusion rate in DES. These factors lead to the rapid depletion of melamine monomer in the electrode-solution interface diffusion layer by electro-generated active chlorine, ultimately preventing the effective deposition of pMel films. By leveraging the high solubility of melamine in DES, we successfully achieved pMel synthesis under anhydrous conditions in Ethaline and Glyceline by appropriately increasing the melamine monomer concentration or applying stirring. The formation process and morphological structure of the pMel deposition layer were confirmed using cyclic voltammetry (CV), quartz crystal microbalance (EQCM), and atomic force microscopy (AFM).