Plasmonic Anti‐counterfeiting Labels Based on the Au@SiO2‐Embedded Electrospun Fibers

Abstract

AbstractA new type of plasmonic anti‐counterfeiting labels is designed on the basis of Au@SiO2 core–shell nanoparticles (Au@SiO2 NPs) and electrospun fibers. The fingerprint information of Raman active molecules is amplified by the plasmonic Au nanoparticles, and silica layers endow the stability of encoding information. Electrospun fibers with unordered breathable structure play the role of polymer matrix and own the flexible features. Au@SiO2 NPs are first adsorbed on the surface of poly(methyl methacrylate)/poly(4‐vinylpyridine) (PMMA/P4VP) fibers by noncovalent interactions, and then are decorated in/on the fibers by controlling the temperature. That is, when the temperature is higher than the glass transition temperature (Tg) of polymer matrix, partial Au@SiO2 NPs are embedded in the PMMA/P4VP fibers. The composite fibers based on the Au@SiO2 and PMMA/P4VP fibers are fabricated, and the signals of Raman active molecules are amplified in the Au@SiO2/PMMA/P4VP fibers. The peak positions and intensity of spectra from surface‐enhanced Raman spectroscopy are transferred into plasmonic anti‐counterfeiting labels with different spaces and widths. The anti‐counterfeiting labels are further encrypted into quick response (QR) codes and decrypted by the smartphone. The QR codes are difficult to copy and easy to authenticate, and composite fibers possess superior stability and show potential application in the field of anti‐counterfeiting.