Michael Mayer and colleagues at Texas Tech University in Lubbock have demonstrated a process for creating a slip-linked pulley system of molecules - polypseudorotaxanes - via the ring-opening metathesis polymerization of catenanes. Their approach could be used to create tougher and more elastic synthetic materials. In a sense, the work combines features of conventional polymer chemistry with cutting-edge supramolecular chemistry research. "No one has ever reported making polymers in this way," says Mayer, "It is a fundamentally new, stripped-back approach to the synthesis of this class of polymeric materials." The key feature of the new materials is that they have rings that can slide along the polymer chains, providing moveable anchor points for cross-linking.