The starting morphology used for the preparation of the syndiotactic polystyrene (sPS)/solvent complex, has a significant role in facilitating the phase transitions of the host structure upon guest exchange process. This effect was studied on the structural changes of sPS, using guest exchange process, with a series of n-alkanes, and analyzed by X-ray diffraction and Fourier transform infrared spectroscopy. SPS solvent complexes (monoclinic (delta form) were prepared with different starting morphologies i.e. amorphous, alpha and gamma forms using toluene and chloroform as guests. Upon guest exchange process (performed by dipping the samples in a series of n-alkanes viz, n-octane to n-decane), toluene treated amorphous and a form samples (i.e. monoclinic (delta form) transformed into the triclinic (delta form irrespective of the starting morphology. However, the toluene treated y form transformed back to the y form in presence of n-alkanes. Chloroform treated amorphous sample (i.e. monoclinic epsilon form), however, converted to a mixture of form (triclinic) and e form, while chloroform treated a and y forms transformed into triclinic delta form and gamma form, respectively. Besides host preparation method, influence of starting delta form crystallinity on the guest exchange process was also examined. (C) 2013 Elsevier Ltd. All rights reserved.