How a Family of Nanostructured Amphiphilic Block Copolymers Synthesized by RAFT-PISA Take Advantage of Thiol Groups to Direct the In Situ Assembly of High Luminescent CuNCs within their Thermo-responsive Core

Abstract The development of fluorescent water stable copper nanoclusters (CuNCs) deserves the scientific interest due to their outstanding properties and low-cost. These fluorescent CuNCs can be synthesized using natural or synthetic polymers with thiol groups. Herein, for the first time, we propose the use of novel amphiphilic block copolymer nano-objects, synthesized by polymerization induced self-assembly (PISA) via reversible-addition fragmentation chain transfer (RAFT), as templates for the synthesis and water stabilization of CuNCs. The polymeric NPs provide water-stability due to the poly(hydroxyethyl acrylate) corona and the thermos-responsive core, based on 2-(2-methoxyethoxy) ethyl methacrylate (MEO2MA) and 2-(acetylthio) ethyl methacrylate (AcSEMA) decorated with protected thiol groups, drive the “in situ” reduction of copper ions into copper nanocrystals and their assembling in high luminescent nanohybrids in water. In order to optimize the fluorescence properties a methodical study was carried out varying polymers composition and architecture, thiol content and nanoparticle size. All the polymeric nanoparticles synthesized by PISA and decorated with thiol groups induce the formation of luminescent CuNCs in their hydrophobic core. The sizes of the hydrophilic/hydrophobic block, as well as, thiol content are key factors in the emission properties of the CuNC nanohybrids that offer high colloidal stability in water, pH- and thermo-response, significance photostability and strong resistance to oxidation.