Mechanochromism and Mechanical‐Force‐Triggered Cross‐Linking from a Single Reactive Moiety Incorporated into Polymer Chains

Abstract
Incorporation of small reactive moieties, the reactivity of which depends on externally imposed load (so-called mechanophores) into polymer chains offers access to a broad range of stress-responsive materials. Here, we report that polymers incorporating spirothiopyran (STP) manifest both green mechanochromism and load-induced addition reactions in solution and solid. Stretching a macromolecule containing colorless STP converts it into green thiomerocyanine (TMC), the mechanically activated thiolate moiety of which undergoes rapid thiol–ene click reactions with certain reactive C=C bonds to form a graft or a cross-link. The unique dual mechanochemical response of STP makes it of potentially great utility both for the design of new stress-responsive materials and for fundamental studies in polymer physics, for example, the dynamics of physical and mechanochemical remodeling of loaded materials.
Funding Information
  • National Natural Science Foundation of China (21304076)
  • China Postdoctoral Science Foundation (2014T70612)
  • Natural Science Foundation of Fujian Province (2014J01060)
  • UK Engineering and Physical Sciences Research Council (EPSRC)