On-surface radical addition of triply iodinated monomers on Au(111)-the influence of monomer size and thermal post-processing

► Triply iodinated monomers spontaneously polymerize on Au(111) at room temperature. ► No further thermal activation is needed to split-off iodine substituents. ► Split-off iodine atoms adsorb strongly and form ordered superstructures. ► Post-processing through thermal annealing leads to increased domain sizes. ► Smaller, less flexible monomers yield covalent networks with less defects.