Synthesis of Polyurethane with Mechanical Properties Responsive to Water Retention States

Whether running or driving, slippery surfaces have always been the enemy of speed and safety. In this work, water-retention-state-responsive polyurethane (WRSRPU) was synthesized via introducing zwitterionic sulfobetaine (SB) onto its polymer chains. With strongly hydrophilic properties, the SB segment, when its content is increased to a certain level, is able to significantly change the mechanical properties, e.g., the modulus and tribological behavior, of thus-obtained polyurethane upon exposure to wet conditions, and these properties are reversible via switching the water absorption and release behavior. Even at different humidity levels, the mechanical properties of polyurethane can change significantly with an increase in water absorption. This unique water-responsive behavior of thus-obtained polyurethane opens up a stable and proactive approach for solving the problem of skidding under wet conditions, which is a long-established troublesome issue in daily life, sports, and transportation.