Conventional chain-growth polymerization involves at least two phases; initiation and propagation, while  and in some cases termination and chain transfer phases also occur.  Chain-growth supramolecular polymerization in a broad sense involves two distinct phases; a less favored nucleation and a favored propagation.  In this mechanism, after the formation of a nucleus of a certain size, the association constant is increased, and further monomer addition becomes more favored, at which point the polymer growth is initiated.  Long polymer chains will form only above a minimum concentration of monomer and below a certain temperature.  However, to realize a covalent analogue of chain-growth supramolecular polymerization, a challenging prerequisite is the design of appropriate monomers that can polymerize only by the action of initiators.  Recently one example of chain-growth supramolecular polymerization with "living" characteristics is demonstrated.  In this case, a bowl-shaped monomer with amide-appended side chains form a kinetically favored intramolecular hydrogen bonding network and does not spontaneously undergo supramolecular polymerization at ambient temperatures.  However, an N-methylated version of the monomer serves as an initiator by opening the intramolecular hydrogen bonding network for the supramolecular polymerization, just like ring-opening covalent polymerization.  The chain end in this case remains active for further extension of supramolecular polymer and hence chain-growth mechanism allows for the precise control of supramolecular polymer materials.