研究目的

Investigating the changes in the extinction spectra of a nanocomposite consisting of Ag nanoparticles arranged into poly(glycidyl methacrylate) host matrix under the influence of chloroform vapor.

研究成果

The nanocomposite comprises polymer PGMA matrix and embedded 2D array of Ag nanoparticles was prepared. The structure of the extinction spectrum of such composite is governed by collective surface plasmon mode excited in the Ag NPs array. The mode can be decomposed into two components with different orientation of charge oscillations. When oscillations in metal nanoparticle are parallel to the plane of 2D NPs array the mode is denoted as T (tangential). P or normal mode corresponds to charge oscillations orthogonal to the plane of the 2D array. It was found experimentally that spectral bands associated with normal and tangential components of the plasmon mode change their intensity, spectral width and position when the nanocomposite is exposed to organic vapors. The bands exhibit decrease of area, blue shift and spectral narrowing with the increase of vapor concentration. This is due to enlarging the spacing between neighboring NPs in the array provoked by swelling of the PGMA polymer film. At the same time, the refractive index of the polymer decreases with swelling. Those two processes weakens electrodynamic interaction between LSPR in adjacent Ag NPs that explains the observed spectral changes. Sensitivity of the nanocomposite to chloroform vapor is 0.02 nm/ppm, while its response time t≈25 s. Our results may find applications in sensor technology and optoelectronics.

研究不足

The study is limited to the detection of chloroform vapor and does not explore the sensitivity of the nanocomposite to other organic vapors.