Direct Functionalization of Polyethylene Surfaces with High-Density Polymer Brushes

Introducing functionality onto PE surfaces is a longstanding challenge in polymer science, driven by the need for polymer materials with improved adhesion and antifouling properties. Herein, we report surface-initiated hydrogen atom transfer-reversible addition-fragmentation chain transfer (SI HAT-RAFT) as a robust method to grow high-density brush polymers from PE surfaces. We demonstrate that, under mild conditions, direct initiation from the C-H bonds of PE surfaces allows for the graft polymerization of a variety of (meth)acrylate monomers. The resulting polymer brushes reached several hundred nanometers in thickness with densities of ca. 0.62 chains/nm², compared to the current standard of ∼0.28 chains/nm². Finally, we show that our method is capable of dramatically improving the adhesive properties of PE surfaces. This work enables the preparation of PE with diverse surface functionalities for potential use in biomedical, industrial, and battery applications.