Epitaxial or oriented growth of flexible chain polymer crystals on crystalline substrates, such as mica, NaCl or KBr, can occur from solution or the melt.

   Epitaxial crystallization of a polymer on the surface of a highly oriented crystalline film of another polymer has been carried out by pressing thin film of the two polymers together and applying a tensile stress during the melt crystallization process.

   A schematic representation

Fig. 19. Epitaxial lamellar crystallization on polymer fibrils.

Fig. 20. Shish-Kebab crystal structure

  Lamellar crystallization of one polymer on fibers of another can occur, as shown in Figure 21; the epitaxial growth of the natural polymer, on cellulose fibrils during crystallization from solution is shown in this figure.

Fig. 21. Transmission electron micrograph of (fractionated) mannan lamellas epitaxially grown on cellulose fibrils from dilute NaOH solution at elevated temperature by addition of dimethylsulfoxide.