A novel fluorinated capping agent and silicone synergistically enhanced waterborne polyurethane

While waterborne polyurethanes (WPUs) have been applied to a broad range of fields, poor hydrophobic, water-resistant, and mechanical properties still limit their further development. Herein, we report a novel WPUs by an elaborate molecular design that 1 H,1 H,2 H,2 H,3 H,3 H-tridecafluoro-1-nonanol (TFN) was used as a capping agent at the end of the polyurethane chain, and polydimethylsiloxane (PDMS) used as a soft segment in the middle of the chain to synergistically enhance its properties. The TFN at the end of the polyurethane chain broke through the chain movement limitation, largely improving the surface hydrophobicity of coating, realizing the change from hydrophilic to hydrophobic with the water contact angles increased from 88.5° to 128.6°. PDMS as the soft segment increased the phase separation of polyurethane due to the thermodynamic immiscibility, improving the mechanical properties without sacrificing the hydrophobicity. Meanwhile, the water-resistant performance was also improved with the incorporation of PDMS. As a result, the hydrophobicity, water-resistance, and mechanical properties of as-synthesized WPUs coating can be improved simultaneously through the sophisticated molecular design, thus offering the potential to expand their applications.