Under near-equilibrium conditions, solids form from aqueous solutions via the addition of monomer growth units. The terrace, ledge, and kink (TLK) model and the Burton–Cabrera–Frank (BCF) theory give reasonable descriptions of this process. At higher degrees of supersaturation, monomers addition is joined by the accretion of polymer and larger growth units, up to and including stable crystallites. The solids formed by accretion of these larger units are often metastable and eventually transform to more stable forms. This means that the formation of a stable crystalline solid from a very supersaturated solution involves several steps. This chapter presents models that describe the formation and accretion of larger growth units and transformation of the resulting metastable solids.

Polymerization rates

Polymers such as DNA, proteins, polysaccharides, and polyphenols are essential components of organisms; and synthetic polymers such as Nylon, polyethylene, styrene, and Teflon are basic raw materials for modern technology, so it is not surprising that there is a rich literature about the formation of polymers. Most of that literature focuses on the formation of biopolymers and plastic but the polymerization models (Dotson et al., 1996) for those cases are potentially useful to geochemists.