A general stepwise strategy for the preparation of new humidity-responsive plasmonic nanosensor was described for the first time, based on Ag film functionalization by polyacrylamide（PAAM） brushes via surface-initia...A general stepwise strategy for the preparation of new humidity-responsive plasmonic nanosensor was described for the first time, based on Ag film functionalization by polyacrylamide（PAAM） brushes via surface-initiated atom transfer radical polymerization（SI-ATRP） method and then assembled with gold nanoparticles（Au NPs）. We designed by this way a new plasmonic device made of Au NPs embedded in a humid vapor responsive polymer layer on Ag film and extensively characterized by surface-enhanced Raman scattering（SERS）. When the relative humidity（RH） is above 50%, the number of plasmonic hotspots decreases, causing SERS signal reduced noticeably, for the volume expansion of PAAM brushes varied the nano-gap between closely spaced Au NPs, and between Au NPs and Ag film. The reversible optical properties of the prepared nanocomposite tuned by RH were probed through SERS using 4-mercaptopyridine（4-Mpy） as a molecular probe, and the decrease of the RH reversibly induces a significant enhancement of the 4-Mpy SERS signal. By means of the high reversibility, the RH responsive nanocomposite developed in this paper provides a dynamic SERS platform and can be applied as plasmonic nanosensor which is proved to be stable for at least two months.展开更多
基金supported by the National Natural Science Foundation of China (51572009)
文摘A general stepwise strategy for the preparation of new humidity-responsive plasmonic nanosensor was described for the first time, based on Ag film functionalization by polyacrylamide（PAAM） brushes via surface-initiated atom transfer radical polymerization（SI-ATRP） method and then assembled with gold nanoparticles（Au NPs）. We designed by this way a new plasmonic device made of Au NPs embedded in a humid vapor responsive polymer layer on Ag film and extensively characterized by surface-enhanced Raman scattering（SERS）. When the relative humidity（RH） is above 50%, the number of plasmonic hotspots decreases, causing SERS signal reduced noticeably, for the volume expansion of PAAM brushes varied the nano-gap between closely spaced Au NPs, and between Au NPs and Ag film. The reversible optical properties of the prepared nanocomposite tuned by RH were probed through SERS using 4-mercaptopyridine（4-Mpy） as a molecular probe, and the decrease of the RH reversibly induces a significant enhancement of the 4-Mpy SERS signal. By means of the high reversibility, the RH responsive nanocomposite developed in this paper provides a dynamic SERS platform and can be applied as plasmonic nanosensor which is proved to be stable for at least two months.
