Ionic polymerization is a type of chain-growth polymerization that involves the use of ionic species, such as cations or anions, to initiate the reaction. This process allows for the rapid formation of polymers by adding monomer units one at a time, resulting in long chains. The ionic initiators can be generated from various sources, including Lewis acids or strong bases, which help to create reactive sites on the monomers. This method is particularly useful for producing specific types of polymers with desired properties, such as polystyrene or polyethylene oxide. Ionic polymerization can be controlled to achieve different molecular weights and structures, making it a valuable technique in materials science and industrial applications.