Integral and Nonintegral Folding in Lamellar Crystals of Molecular Complexes of Poly(ethylene oxide)

Abstract

The morphology of poly(ethylene oxide) (PEO) complexes crystallized from the melt is investigated by small angle X-ray scattering and differential scanning calorimetry. The formation of integral folded chain crystals with either extended chains (EC) or x -folded chains is observed for the PEO−resorcinol complex. As for pure PEO oligomers, the fraction of EC crystals increases with the crystallization temperature to give finally only EC crystals but in a larger range of crystallization temperatures. On the other hand, the PEO− p -nitrophenol complex crystallizes over all the studied temperature range as stable nonintegral folded chain crystals. These two different lamellar morphologies are related to the crystal structure of these complexes and their mode of growth.