with chemical doping, the electronic characteristics of peapods can be further adjusted. when carbon peapod is doped with alkali metal atoms like potassium, the dopants will react with the c molecules inside the swnt. it forms a negatively charged c covalently bound, one-dimensional polymer chain with metallic conductivity. overall, the doping of swnts and peapods by alkali metal atoms actively enhances the conductivity of the molecule since the charge is relocated from the metal ions to the nanotubes.