Poly(Acrylic Acid) and silver nanoparticle hybrid microgel for sensitive SERS pH detection

• pH sensitive pAA microgels crosslinked with BAC were synthesized. • Microgel surface was covered with Ag NPs through the chemisorption process. • pH-induced microgel volume changes on the SERS response of AgNPs was investigated. • Hybrid microgel for highly sensitive SERS-based pH detection. In this work, we present a novel hybrid microgel composed of pH-responsive poly(acrylic acid) microgel and silver nanoparticles (AgNPs), designed for highly sensitive SERS-based pH detection. The poly(acrylic acid) microgel network was crosslinked using N , N’ -bis(acryloyl)cystamine (BAC), whose disulfide bridges facilitated the attachment of AgNPs to the microgel surface via chemisorption through silver-sulfur interactions. The physical and chemical properties of the hybrid microgel were thoroughly characterized using Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), transmission electron microscopy (TEM), and Energy-Dispersive X-ray Spectroscopy (EDS). Additionally, the impact of pH-induced microgel volume changes on the Surface-Enhanced Raman Scattering (SERS) response of AgNPs was investigated. The results revealed a strong correlation between the SERS signal intensity and environmental pH, highlighting the potential of these hybrid materials as pH-sensitive SERS platform.