On-demand click functionalization of polyurethane films and foams

A novel platform of side-chain functionalized crosslinked polyurethane (PU) films and foams has been used to afford new classes of PU materials. Indeed, alkyne pendant groups located along the polyurethane backbone have been modified via the copper catalyzed Huisgen 1,3-dipolar cycloaddition with various azide components. These cycloaddition reactions were carried out in water or in a mixture of water/acetone under mild conditions (room temperature to 50 °C) in the presence of low amounts of copper catalyst. The resulting functionalized films and foams were all characterized by FT-IR, contact angle measurements and confocal fluorescence microscopy. All these techniques successfully proved that the click chemistry process is valuable in functionalizing PU films and foams in an easy way. The post-functionalization of these alkyne-functionalized PUs afforded the creation of new classes of PU materials with easily adaptable physical properties by choosing the appropriate azide component.