Iron–Gold Galvanic-Assisted Rapid Grafting of Polymer Brushes on n‑Silicon for a Triboelectric Nanogenerator

The surface-initiated iron(0)-mediated controlled radical polymerization (SI-Fe⁰CRP) has attracted considerable interest in interface modification because it allows the controlled growth of various polymer brushes on arbitrary substrates under ambient conditions. In order to further expand the polymer brush for different application fields, herein, we propose a robust approach, namely, galvanic-cell-assisted surface-initiated Fe(0)-mediated atom transfer radical polymerization (gc-SI-Fe⁰ATRP). In gc-SI-Fe⁰ATRP, an iron-based galvanic cell allows continuous and rapid dissociation of Fe ions in an aqueous environment due to the galvanic-effect-accelerated corrosion of Fe. Through this approach, microliter volumes of various vinyl monomers could be rapidly converted to polymer brushes (up to 864 ± 67 nm in 30 min) with excellent controllability and chain-end fidelity (e.g., the successful preparation of the triblock brushes). We also demonstrate that the gc-SI-Fe⁰ATRP could efficiently polymerize ionic poly(methacryloyloxy)ethyl trimethylammonium chloride (PMETAC) brushes on large-area n-type silicon for a triboelectric nanogenerator (PB-TENG), which provides an excellent power output of 4.97 μW m^–2, more than 11 times higher than the TENG without polymer brush grafted. This work demonstrates an efficient strategy for synthesizing polymer brushes and their potential in the functionalized electrodes for TENGs.