Thiolated RAFT-PISA nano-templates power on luminescent copper nanoclusters (CuNCs) for selective mercury (II) detection

Abstract

In this study, we expand the scope of polymerization-induced self-assembly (PISA) by modifying one of the most prototypical copolymers derived from RAFT-mediated PISA, poly(glycerol methacrylate)-b-poly(hydroxypropyl methacrylate) (pGMA-b-pHPMA), by incorporating a comonomer with a protected thiol group-2-(acetylthio)ethyl methacrylate (AcSEMA) into the hydrophobic block. The photoinitiated synthesis of pGMA-b-p(HPMA-co-AcSEMA) was conducted in a water/ethanol mixture (60/40 v/v) to increase the solubility of AcSEMA. Thus, this modification enabled the formation of diverse polymeric nano-morphologies such as spheres, worms, and vesicles, dictated by the balance between hydrophilic and hydrophobic block ratios and the AcSEMA content. Besides, the strong metal affinity of thiol groups makes the incorporation of AcSEMA into self-assembled nanostructures a versatile platform for generating advanced hybrid materials with potential applications in biomedicine, sensing, catalysis, or water purification. As evidenced in this work, the post-hydrolysis of the thioacetate group into thiol allowed the use of polymeric nano-objects as templates to power on the luminescenece of functionalized copper nanoclusters (CuNCs). These polymeric CuNCs, composed of several to hundreds of copper atoms, exhibit remarkable red emission, positioning the synthesized hybrids as promising luminescent probes for the development of highly selective “switch-off” luminescent sensors for Hg²⁺ detection. This work paves the way for the design of multifunctional hybrid nanomaterials with advanced applications.