Investigation of the SERS application of gold films deposited on uncured polydimethylsiloxane with tunable LSPR

Abstract

We present an approach to investigate the localized surface plasmon resonance and surface-enhanced Raman scattering of gold films deposited on uncured polydimethylsiloxane via thermal evaporation. Differing from solid substrates, the liquid surface of uncured polydimethylsiloxane can serve as an isotropic substrate on which gold atoms nucleate and disperse to form characteristic microstructures in a controlled manner. By adjusting experimental parameters during film deposition, the absorption of resonant plasmon modes can be tuned in the visible spectral range due to the control of particle size and distribution in Au films. Furthermore, Raman measurements are conducted to investigate the enhancement of Raman signals in these films, and the experimental results are verified by simulation analysis. This work exhibits tunability of surface plasmon resonance frequency and enhanced Raman detection capability by depositing metal films on liquid surfaces, thus providing potential applications of these films in flexible biosensors and chemical detection.

Removable PDMS Films with Ultra‐Low AgNPs Content and Effective SERS Effect by N‐Octylamine Transfer and Immersion Deposition

“…Although the mineral sample was acquired as azurite, the peaks at 121, 194, and 458 cm À 1 found in the Raman-SERS analysis are associated with a quartz mineral as it can be seen in Figure a) where the mineral sample is compared with a known fragment of quartz that has the correspondent Raman bands of quart (14,1945 and 1945 cm À 1 ). SEM micrographs and EDS analysis revealed that the blue mineral is mainly composed of a heterogeneous mixture of two phases (Figure b), with copper and silicon being the two main constituents of these phases (encircled areas in Figure b).…”

“…On the other hand, although the use of metallic nanoparticles in suspension is an alternative to generate the SERS effect, this effect can also be obtained by immobilizing nanoparticles on solid substrates. [10,14] According to this aspect, in recent years it has sought to develop removable devices that meet the objective of presenting the SERS effect, and that can be used to analyze different types of analytes without interfering with the integrity of the sample. [15,16] Immobilization of metal nanoparticles on flexible substrates such as gelatin, [17] or methylcellulose pastes, [18] the use of organic polymer-based substrates such as poly(vinyl pyridine) to deposit silver nanoparticles, [19] or poly(vinyl pyrrolidone) to deposit gold nanoparticles, [20] and more recently the use of poly(dimethyl siloxane) (PDMS) to immobilize AgNPs [21,22] are some promising alternatives developed that could achieve such a goal.…”

“…The direct application of AgNPs for the analysis of cultural heritage materials by drop casting has allowed the identification of natural resins as well as natural and synthetic dyes; [12,13] however, the study of pieces of historical and cultural interest requires non‐destructive and minimally invasive analysis as possible; therefore, because the suspended nanoparticles must be in contact or mixed with the analyte sample to obtain the SERS effect, their use is limited in this type of pieces. On the other hand, although the use of metallic nanoparticles in suspension is an alternative to generate the SERS effect, this effect can also be obtained by immobilizing nanoparticles on solid substrates [10,14] . According to this aspect, in recent years it has sought to develop removable devices that meet the objective of presenting the SERS effect, and that can be used to analyze different types of analytes without interfering with the integrity of the sample [15,16] .…”

“…[10,14] According to this aspect, in recent years it has sought to develop removable devices that meet the objective of presenting the SERS effect, and that can be used to analyze different types of analytes without interfering with the integrity of the sample. [15,16] Immobilization of metal nanoparticles on flexible substrates such as gelatin, [17] or methylcellulose pastes, [18] the use of organic polymer-based substrates such as poly(vinyl pyridine) to deposit silver nanoparticles, [19] or poly(vinyl pyrrolidone) to deposit gold nanoparticles, [20] and more recently the use of poly(dimethyl siloxane) (PDMS) to immobilize AgNPs [21,22] are some promising alternatives developed that could achieve such a goal. However, one of the problems in using SERS substrates based on organic polymers is that they are hydrophobic, so it is not possible to directly deposit the aqueous colloid solution obtained during the Lee-Meisel method of synthesis.…”

Direct detection of nitrite and nitrate in water on three-dimensional composite surface-enhanced raman scattering substrate

“…However, Raman signals are characteristically weak. To amplify weak Raman signals, the surface-enhanced Raman scattering (SERS) technique is applied [5], which greatly enhances the Raman signal when the sample molecules on the surface of rough precious metals are in the range of several nanometers. Two methods are used to detect nitrites and nitrates in water using SERS: indirect and direct [6,7].…”