Determination of the Extent of Lateral Spread and Density of Secondary Nucleation in Polymer Single Crystal Growth

As illustrated in an earlier work (Macromolecules 2006, 39, 1008), isotactic poly(vinylcyclohexane) (PVCH) single crystals display twinned growth sectors. Mapping of the twinned domains is possible via dark-field electron microscopy imaging. Each twinned domain results from a growth twin on the lateral growth face of the single crystal. The width of the twinned domain provides a measure of the so-called lateral spread extent, a fundamental parameter of classical theories of nucleation and growth for which only indirect estimates are available. The extent of lateral spread (and, as a corollary, the secondary nucleation density) (both average values and distribution), are determined for single crystals of PVCH produced in squalane over a wide range of crystallization temperatures (120−240 °C). These observations provide the first direct experimental data on these elementary processes in polymer crystal growth.