What type of polymerization involves the nucleophilic attack of an initiator on a monomer with a double bond?

The type of polymerization that involves the nucleophilic attack of an initiator on a monomer with a double bond is free radical polymerization. In this process, a free radical, which can be generated from an initiator, attacks the double bond of a monomer, leading to the formation of a new radical. This newly formed radical can then react with other monomers, effectively propagating the polymer chain.

Free radical polymerization is characterized by three main steps: initiation, propagation, and termination. In the initiation step, the initiator generates free radicals that engage with the double bonds of vinyl monomers. The initial attack opens the double bond, allowing the monomer to integrate into the growing polymer chain. This reaction continues, as each newly formed radical can react with additional monomers, leading to an increase in the length of the polymer chain until termination occurs.

In the context of the options provided, other forms of polymerization typically involve different mechanisms. For example, condensation polymerization involves the stepwise reaction of monomers with the elimination of small molecules like water, rather than a free radical mechanism. Ionic polymerization, which can include both cationic and anionic processes, involves the attack of ions on the double bonds, but