Preparation and catalytic properties of modified PGMA‐based pH‐responsive hydrogel films as a novel template for in situ synthesis of Au, Ag, and Au:Ag nanoparticles

Abstract

ABSTRACTMetal‐nanoparticle (M‐NP)‐modified glycidyl methacrylate (GMA)‐based hydrogel film composites were synthesized and assessed for their catalytic activities by reducing para‐nitrophenol (p‐NP) to para‐aminophenol (p‐AP) with sodium borohydride. Poly(ethylene glycol)methyl ether‐block‐poly(glycidyl methacrylate)‐block‐poly(methyl methacrylate) (MPEG‐b‐PGMA‐b‐PMMA) triblock copolymer was synthesized via atom transfer‐radical polymerization. The epoxy ring of the PGMA blocks was opened by the addition of 1‐methylpiperazine. The resulting bifunctional polymer containing 2‐hydroxy‐3‐methyl piperazinepropyl methacrylate units was used to synthesize novel crosslinked hydrogel films by quaternization of the tertiary amine (methylpiperazine) with 1,2‐bis(2‐iodoethoxy)ethane. The synthesized hydrogel film swelled in aqueous solution when the pH was changed from basic to acidic. The prepared MPEG‐b‐PHMPPMA‐b‐PMMA hydrogel film was used as an immobilizing matrix to form monometallic silver (Ag) and gold (Au) and bimetallic alloy gold:silver (Au:Ag) nanoparticles. The M‐NP/hydrogel film composites were characterized by transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, and ultraviolet–visible spectrophotometry. The synthesized M‐NP/hydrogel film composites showed good catalytic activity to reduce p‐NP to p‐AP. The composites were also found to be reusable as their activity only slightly dropped after 10 consecutive uses. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48360.