Epitaxial crystallization of isotactic and syndiotactic polypropylene

Epitaxy is defined as the growth of one crystalline phase (the guest crystal, here the polymer) on the surface of a crystal of another phase (the host crystal, here the substrate) in one or more strictly defined crystallographic orientations. The interactions imply a structure analogy between the two species in their contact planes, either in two, or sometimes only one direction. The details of the molecular interactions may be difficult to reach, and, as a consequence, the epitaxy is often defined in terms of a geometrical concordance of matching unit-cell dimensions the disregistries should remain 10%. 

Polymer/substrate epitaxial interactions are of interest in order [1]  

to produce well-oriented polymer thin films well adapted for morphology and structural analyses by electron microscopy and electron diffraction  

to produce well-defined exposed crystalline surfaces highly appropriate for combined electron diffraction-atomic force microscopy (AFM) molecular modelling studies  

to understand the mechanisms of action and the efficiency of nucleating agents for polymers, and therefore establish guidelines for the search and design of new, or more eflfective, nucleating additives. 

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