Controlling the Mechanical Response of Polymers via Metal Induced Coordination Conformational Changes

The modulation of mechanical properties in polymers with metal binding ligands has largely been achieved via crosslinking between polymer chains induced by metal ion binding to pendant or end ligating groups. In this work, incorporation of ethylenediaminetetraacetic acid (H₄edta) into the main chain backbone of flexible, linear polymers results in substantial modulation of mechanical properties via conformational changes in the imbedded ligand within the polymer backbone induced by metal ion binding. Upon the addition of metal ions, these polymers transform from viscous liquids into solids with improved elastic characteristics. Polymer strength and toughness are significantly enhanced without the need for extensive polymer crosslinking. This approach represents a new paradigm in using metal ions to modulate the mechanical properties of organic polymers.