The structure and dynamics of PEO chains encapsulated in thiourea (TU) channels formed in the PEO-TU-inclusion compound (PEO-TU-IC) were studied by XRD, FTIR and solid state NMR spectroscopy. XRD and FTIR observations clearly show PEO-TU-IC adopts a crystal structure different from neat thiourea, and the usual rhombohedral crystal structure of thiourea small molecule ICs. PEO chains in the channel adopt a conformation similar to bulk PEO, as confirmed by solid state NMR spectroscopy. Contact-time array (VCT) NMR profiles shows that PEO chains in the TU channels are considerably more mobile than in bulk PEO. Infrared bands for the PEO shift in the IC, and these were attributed to changes in the secondary forces. (c) 2007 Elsevier Ltd. All rights reserved.