Novel data about the crystal morphology and the electron diffraction of syndiotactic poly(p-methylstyrene) (s-PPMS) in form I and in the clathrate forms including o-dichlorobenzene and tetrahydrofuran are presented. Preparative routes of s-PPMS samples in the various polymorphs suitable for electron microscopy and diffraction have been devised. This investigation provides data, unavailable in the past literature, helpful to get direct structural information and to better understand the ways of obtaining and stabilizing the various polymorphs. (C) 2000 Elsevier Science Ltd. All rights reserved.