Color Transferability from Solution to Solid Using Silica Coated Silver Nanoparticles

The interpretation of color change in sensors and tests can be linked to incorrect conclusions if the intrinsic color changes are not accounted for. In this work, we study the intrinsic color change associated with the process of embedding nanoparticles in a polymer to create nanocomposite films. We present a safer, faster method to coat silver nanoparticles with silica and employ a seven-factor Plackett-Burman design to identify critical factors in the synthesis. Silver nanodisks with increasing thicknesses of the silica shell showed a decreasing sensitivity of their localized surface plasmon resonance (LSPR) toward changes in the refractive index surrounding the nanoparticle. A color shift of up to 72 nm was observed when bare nanoparticles were embedded in poly(vinyl alcohol), but no color change was perceived when nanoparticles were coated with a 25-nm-thick silica shell. Understanding the origin of color changes intrinsic to the preparation of polymeric nanocomposites aids in the design and correct use of plasmonic sensors.

Automated summary

The intrinsic color change in the preparation of polymeric nanocomposites was studied in this work. A safer and faster method to coat silver nanoparticles with silica was presented and critical factors in the synthesis were identified using a seven-factor Plackett-Burman design. The sensitivity of the localized surface plasmon resonance (LSPR) of silver nanodisks towards changes in refractive index decreased with increasing thickness of the silica shell. A color shift of up to 72 nm was observed when bare nanoparticles were embedded in poly(vinyl alcohol), but no color change was perceived when the nanoparticles were coated with a 25-nm-thick silica shell.