Flexible, robust, and highly stable gold nanoparticle-decorated aramid nanofiber SERS substrates for ultrasensitive detection of hazardous chemicals in harsh environments

Abstract

Surface-enhanced Raman scattering (SERS) has emerged as a powerful analytical technique with broad applications spanning materials science, environmental monitoring, food safety, biomedical diagnostics, and cultural heritage preservation. Despite its widespread adoption, the development of SERS substrates capable of operating in harsh environments remains largely unexplored. To address this challenge, we present a robust SERS platform based on aramid nanofibers (ANFs), which combine exceptional flexibility, outstanding mechanical strength, and remarkable thermal/chemical stability. Through a facile, environmentally benign, and scalable magnetron sputtering approach, we achieve uniform deposition of high-density gold nanoparticles (AuNPs) onto ANF membranes, creating flexible AuNPs@ANF hybrid substrates. A systematic investigation of sputtering time reveals its critical role in optimizing the SERS performance of these substrates. The optimized Au-150@ANF substrate with a sputtering time of 150 s demonstrates high detection sensitivity of 10^-8 M for rhodamine 6G molecules, exceptional signal reproducibility, and storage stability. Due to its excellent flexibility and mechanical strength, the Au-150@ANF SERS substrate also demonstrates high detection sensitivity for the pesticide residue of thiram on irregular food surfaces using a simple wiping method. Remarkably, the AuNPs@ANF SERS substrate maintains exceptional detection sensitivity toward malachite green (MG) molecules even after aggressive environmental exposure, including immersion in concentrated acids, alkaline solutions, and prolonged thermal stress. Therefore, flexible, robust, and highly stable AuNPs@ANF SERS substrate shows great potential for detecting harmful substances in harsh environments.

Keywords: Aramid nanofibers; Gold nanoparticles; Harsh environments; Surface-enhanced Raman scattering; Toxic materials.