One‐step synthesis of a spongy flexible substrate for surface enhanced Raman spectroscopy comprising a silver nanoparticles‐loaded poly(amidoamine) dendrimer crosslinked with glutaraldehyde

Abstract

A composite comprising a silver nanoparticles‐loaded poly(amidoamine) (PAMAM) dendrimer crosslinked with glutaraldehyde (PAMAM/AgNPs) is synthesized using a one‐step method under vortex at room temperature. The structure of glutaraldehyde‐crosslinked PAMAM dendrimer is characterized using FTIR and high‐resolution magic angle spinning–carbon 13 nuclear magnetic resonance (HRMAS 13C NMR) spectroscopy. The crosslinking structure ensures the uniformity and stability of the Ag nanoparticles, and the flexibility of the PAMAM/AgNPs composite. X‐ray diffraction (XRD) analysis and energy dispersive spectroscopy (EDS) confirm the formation of Ag nanoparticles in the PAMAM/AgNPs composite. Scanning electron microscopy (SEM) and three‐dimensional (3D) micro‐Raman images reveal the coarsely porous 3D micro‐structure of the PAMAM/AgNPs composite. This unique micro‐3D architecture provides the PAMAM/AgNPs composite with spongy flexibility and a swab‐like nature, which is advantageous for the rapid and effective absorption of liquid samples on the surfaces of objects. Surface enhanced Raman spectroscopy (SERS) indicates that the detection limits of both rhodamine 6G (R6G) and thiram are 1.0 × 10−5 mol L−1, and the SERS enhancement factor of R6G is determined to be 1.35 × 104. The spongy flexible PAMAM/AgNPs SERS substrate therefore has potential for use in Raman active compound detection.