Impact of molecular structure of two natural phenolic isomers on the protective characteristics of electropolymerized nanolayers formed on copper

•Electropolymerized layers of Carvacrol (Carv) and Thymol (TOH) were formed on Cu.•FTIR analysis showed the presence of cetonic and ether structures within the layers.•Composition, structure and protective characteristics of the layers were quite different.•PolyCarv layer was transparent and more protective against corrosion than polyTOH.•A high impact of molecular structure on the characteristics of the layers was found.