Versatile flexible SERS substrate for in situ detection of contaminants in water and fruits based on Ag NPs decorated wrinkled PDMS film

Abstract

Flexible surface-enhanced Raman spectroscopy (SERS) substrate has attracted great attention due to its convenient sampling and on-site monitoring capability. However, it is still challenging to fabricate a versatile flexible SERS substrate, which can be used for in situ detection of analytes either in water or on irregular solid surfaces. Here, we report a flexible and transparent SERS substrate based on a wrinkled polydimethylsiloxane (PDMS) film obtained by transferring corrugated structures on the aluminium/polystyrene bilayer film, onto which silver nanoparticles (Ag NPs) are deposited by thermal evaporation. The as-fabricated SERS substrate exhibits a high enhancement factor (∼1.19×105), good signal uniformity (RSD of 6.27%), and excellent batch-to-batch reproducibility (RSD of 7.3%) for rhodamine 6 G. In addition, the Ag NPs@W-PDMS film can maintain high detection sensitivity even after mechanical deformations of bending or torsion for 100 cycles. More importantly, being flexible, transparent, and light, the Ag NPs@W-PDMS film can both float on the water surface and conformally contact with the curved surface for in situ detection. The malachite green in aqueous environment and on apple peel can be easily detected down to 10−6 M with a portable Raman spectrometer. Therefore, it is expected that such a versatile flexible SERS substrate has great potential in on-site, in situ contaminant monitoring for realistic applications.

Flexible Multicavity SERS Substrate Based on Ag Nanoparticle-Decorated Aluminum Hydrous Oxide Nanoflake Array for Highly Sensitive In Situ Detection

“…Mechanical stability is a very important prerequisite for in situ detection on nonplanar objects . Therefore, we first assessed the mechanical properties of this flexible SERS substrate by bending and twisting tests.…”

“…Mechanical stability is a very important prerequisite for in situ detection on nonplanar objects. 49 Therefore, we first assessed the mechanical properties of this flexible SERS substrate by bending and twisting tests. For this test, the multicavity AgNPs@NFA/PDMS films with adsorbed 10 −6 M R6G molecules were consecutively bent or twisted to ∼180°(insets in Figure 5a,c) for 100 cycles.…”

Curvature-Insensitive Transparent Surface-Enhanced Raman Scattering Substrate Based on Large-Area Ag Nanoparticle-Coated Wrinkled Polystyrene/Polydimethylsiloxane Film for Reliable In Situ Detection

“…Additionally, Table S1 presents comparisons of analytical enhancement factor, uniformity, and reproducibility between the Ag NP@W-PS/PDMS substrate and other flexible SERS substrates. The substrate may have exhibited lower enhancement factors compared to some other flexible SERS substrates [ 25 , 29 , 31 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ]. This could be attributed to variations in substrate surface roughness and plasmonic material structure or composition, as well as differences in experimental conditions.…”