Depolymerization of Polymer Brushes Created by SI-PET-RAFT

Controlled polymerization has enabled the precise synthesis of complex polymer architectures, including surface-grafted polymer brushes with diverse functional applications. However, strategies for reversing this process through depolymerization remain underexplored in surface-bound systems. Here, we demonstrate that previously applied solution depolymerization methods can be extended to polymer brushes. Complete depolymerization was achieved for brushes with initial thicknesses of 3–4 nm, while partial depolymerization was observed for thicker brushes, with ∼40% removal at 11–15 nm and ∼25% at 15–45 nm. The depolymerization process was confirmed by nuclear magnetic resonance (NMR) through the detection of monomers in solution. Ellipsometry revealed a decrease in film thickness during depolymerization. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) showed that, at the low thicknesses, the polymer brush was fully removed. These findings demonstrate the potential of polymer brushes created by SI-PET-RAFT as reprocessable surface coatings, as well as their relatively high stability at elevated temperatures, particularly for thicker films (≥15 nm).