A series of poly(ethylene oxide) (PEO)/fullerene(C-60) complexes are prepared by lyophilization. The intermolecular interaction and molecular motion in the complex are investigated by solid-state C-13 NMR spectroscopy. An intense C-60 signal due to the intermolecular cross-polarization is observed in the C-13 CP/MAS spectra of the complex samples, indicating a high degree of dispersion Of C60S in the complexes. By measuring the C-13 spin-lattice relaxation times and H-1 transverse relaxation times of the complex sample and by comparing the static C-13 spectrum of the pure C-60 sample with that of the complex sample, it is demonstrated that there exist n-pi interactions between the n-orbitals of the PEO ether oxygen and the pi-system Of C-60. The C-60 molecules act as physical cross-links in the amorphous region of PEO, which greatly inhibit the mobility of the surrounding PEO chains, while the rapid isotropic rotation Of C-60 molecules is also reduced to some extent due to the interactions with the polymer chains. (C) 2003 Elsevier Science Ltd. All rights reserved.