Abstract: The short range order(0—1.5 nm) in polyether sulfone(PES) copolymer samples were studied. The result showed that two intra-molecular distances in the copolymer repeat unit were successfully resolved in the RDF pattern. However, there were only a suggestions of broad peaks at r≈0.55 nm and r≈1.1 nm attributable to intermolecular ordering, indicating that little intermolecular ordering occurred in either sample. The appearance of the two peaks at ~0.5 nm period suggested the existence of more or less parallel chain segments in PES copolymers. A annealed sample was examined to assess the sensitivity of the RDF method to short range intermolecular ordering. The RDF plot of this annealed sample showed a small variety compared with the quenched PES copolymer sample. The RDF parameter showed that the short range order in PES copolymer samples was essentially affected by the annealing procedures. The results of electron-microscopy investigation of PES copolymer sample, heat-treated at 200 ℃ for 72 h, indicate that the copolymer molecular aggregation is changed from a randomly coiled amorphous phase to an ordered one.

Key words: Polyether sulfone, Radial distribution function(RDF), Short range order structure, Transmission electron microscope(TEM)