Facile One‐Pot Synthesis of Functional Gold Nanoparticle–Polymer Hybrids Using Ionic Block Copolymers as a Nanoreactor

A highly versatile approach to fabricate functional gold nanoparticle (AuNP)‐polymer hybrids is demonstrated by employing sulfonated block copolymers. The 3–5 nm sized ionic domain of the sulfonated poly(styrene‐block‐methylbutylene) (S_nMB_m) copolymers can be utilized as a nanoreactor where the Au ions can be selectively sequestered and reduced to AuNPs using a simple photochemical method. The size of the AuNPs can be adjusted in fine‐steps from 2.0 ± 0.3 to 3.9 ± 0.5 nm by changing the sulfonation levels of the S_nMB_m copolymers. Remarkably, significantly improved methanol oxidation properties are achieved with the hybrid materials owing to the ion conducting–SO₃H groups and the interconnected network of AuNPs confined within the self‐assembled microstructures, which provides electronic conductivity.