Electrostatic-confinement-induced regioselective C-H functionalization of polyolefins.

C-H functionalization shows significant potential for upgrading low-cost semi-crystalline polyolefins. However, current homogeneous functionalization methods encounter an inherent trade-off between crystallinity and functionalization, severely limiting the application of resulting functional polyolefins in both emerging and previously established fields. Here, we demonstrate an electrostatic-confinement-induced C-H functionalization strategy that decouples the functionalization from the crystallinity of resultant functionalized polyolefins in a well-controlled manner. During functionalization, multivalent cations spatially confine electronegative polar functional groups within amorphous domains through electrostatic interactions. This enables highly selective functionalization of amorphous regions at temperature approaching the melting point, yielding functionalized polyethylene exhibiting a higher crystalline fraction, larger crystallite dimensions, and distinct nanoscale sheet-like aggregates of incorporated polar groups. These structural improvements elevate melting temperatures and impart mechanical property enhancement to a typical prototype. This strategy highlights the potential for overcoming traditional crystallinity-functionalization trade-offs in post-polymerization functionalization and offers promising avenues for advanced materials development with target properties.