Polymer multilayers enabled stable and flexible Au@Ag nanoparticle array for nondestructive SERS detection of pesticide residues
Kaiqiang Wang, Da‐Wen Sun, Hongbin Pu, Qingyi Wei
Abstract
The development of flexible and robust plasmonic substrates has become a hot research topic in simplifying and extending the application of surface-enhanced Raman scattering (SERS) technique for real-world analysis. In this work, a facile method to fabricate an [email protected] nanoparticle array sandwiched between the adhesive acrylic polymer tape and polyethene terephthalate (PET) film (T/[email protected]/PET) as a high-performance SERS chip was reported for nondestructive detection of thiram on fruit peels. For this SERS chip, the ordered [email protected] nanoparticle array formed by the self-assembly method was closely-packed, which generated high‐density sub‐3‐nm gaps and could produce high reproducible and sensitive SERS enhancement effects. The measurement of crystal violet with the limit of detection of 7.24 × 10−10 M was realized by targeting Raman shift at 1177 cm−1. Moreover, the excellent flexible feature of acrylic polymer tape enabled the substrate to withstand a tensile strain value of 20% for three cycles without significantly losing its SERS activity. By covering with a PET film, the SERS chip could maintain 87% SERS activity after storage for 60 days in the air environment, and could well withstand the influence of harsh conditions such as high temperature and ultrasound treatments. As a proof of the concept, the SERS tape was directly used to detect thiram on apple, tomato, and cucumber peels via a simple sampling-and-detection procedure, and the detection limit of 5 ng/cm2 was achieved. The T/[email protected]/PET SERS chip should hold a promising candidate for food safety analysis in the future.