Surface Plasmon Resonance Sensitivity Enhancement Based on Protonated Polyaniline Films Doped by Aluminum Nitrate

Abstract

Complex composite films based on polyaniline (PANI) doped hydrochloric acid (HCl) incorporated with aluminum nitrate (Al(NO3)3) on Au-layer were designed and synthesized as a surface plasmon resonance (SPR) sensing device. The physicochemical properties of (PANI-HCl)/Al(NO3)3 complex composite films were studied for various Al(NO3)3 concentrations (0, 2, 4, 8, 16, and 32 wt.%). The refractive index of the (PANI-HCl)/Al(NO3)3 complex composite films increased continuously as Al(NO3)3 concentrations increased. The electrical conductivity values increased from 5.10 µS/cm to 10.00 µS/cm as Al(NO3)3 concentration increased to 32 wt.%. The sensitivity of the SPR sensing device was investigated using a theoretical approach and experimental measurements. The theoretical system of SPR measurement confirmed that increasing Al(NO3)3 in (PANI-HCl)/Al(NO3)3 complex composite films enhanced the sensitivity from about 114.5 [Deg/RIU] for Au-layer to 159.0 [Deg/RIU] for Au-((PANI-HCl)/Al(NO3)3 (32 wt.%)). In addition, the signal-to-noise ratio for Au-layer was 3.95, which increased after coating by (PANI-HCl)/Al(NO3)3 (32 wt.%) complex composite layer to 8.82. Finally, we conclude that coating Au-layer by (PANI-HCl)/Al(NO3)3 complex composite films enhances the sensitivity of the SPR sensing device.

Switchable Polyacrylic Acid Polyelectrolyte Brushes for Surface Plasmon Resonance Applications

“…In addition, the line width (LW) of the recorded image decreased from 6 ± 1 pixels to 5 ± 1 pixels through using the Au-PAA layers, which indicates that the spatial resolution of the recorded image is enhanced. In our previous work [15], we used (PANI-HCl)/Al(NO3)3 Figure 6d demonstrates a local intensity of PSNP detected by the Au layer and Au-PAA layers as a function of the measurement time measured by WF-SPRM. The signal-to-noise ratio (S/N) of the Au-PAA layer is higher than the S/N of the Au layer, which is calculated by studying the line profile plot in the x-direction of the images (Figure 6e,f).…”

“…In addition, the line width (LW) of the recorded image decreased from 6 ± 1 pixels to 5 ± 1 pixels through using the Au-PAA layers, which indicates that the spatial resolution of the recorded image is enhanced. In our previous work [15], we used (PANI-HCl)/Al(NO 3 ) 3 complex composite film as a coating for the Au layer to enhance the sensitivity of the WF-SPRM. We found that the S/N for Au-(PANI-HCl)/Al(NO 3 ) 3 with S/N of 10 ± 1.…”

“…Recently, imaging wide-field SPR microscopy sensors (WF-SPRM) have gained substantial attention in the real-time detection of viruses and virus-like particles due to their capability to measure low particle concentrations with a high sensitivity [14][15][16]. In addition, the WF-SPRM of nano-objects is a spatio-temporal detector based on SPR phenomena for imaging the nano-objects in solution and gas media due to the interaction between nano-objects with the evanescent electrical field near the sensor surface [17][18][19][20][21][22].…”

Optical and electrical properties of polyethylene oxide‐poly(3,4‐ethylenedioxythiophene)/NiZnFeO4 NPs nanocomposite films

“…Conductive polymers have garnered attention from both scientific and industrial perspectives due to their exceptional optical, electrical, and electrochemical properties, as well as their facile processability, controllable chemical properties, and the ability to undergo reversible doping‐dedoping processes 1–3 . The optoelectrical properties of the conductive polymers are related to their conjugated nature and to the polarons formation, which is localized along the polymer chains because of the electron–phonon coupling 4–6 .…”

“…Conductive polymers have garnered attention from both scientific and industrial perspectives due to their exceptional optical, electrical, and electrochemical properties, as well as their facile processability, controllable chemical properties, and the ability to undergo reversible doping-dedoping processes. [1][2][3] The optoelectrical…”