Now that we are familiar with the structures of single chain macromolecules, we are in a position to look at some of the interactions of macromolecules with other macromolecules and with smaller molecules.
Corrosion on exposed metal. Corrosion is a natural process, which converts a refined metal to a more stable form, such as its oxide, hydroxide, or sulfide. It is the gradual destruction of materials (usually metals) by chemical and/or electrochemical reaction with their environment.
Electrochemical corrosion of metals occurs when electrons from atoms at the surface of the metal are transferred to a suitable electron acceptor or depolarizer. Water must be present to serve as a medium for the transport of ions. The most common depolarizers are oxygen, acids, and the cations of less active metals.