Double-C-60-end-capped poly(ethylene oxide) (PEO) possesses good mechanical properties arising from a network-like structure due to the aggregation Of C-60. The tensile strength is about 20 MPa, the elongation at break exceeds 640% and the fracture toughness is more than 110 MJ/m(3). The material also possesses shape recovery ability. In contrast, single-C-60-end-capped PEO does not possess good mechanical properties. (C) 2003 Elsevier Science Ltd. All rights reserved.