Self-assembly of a dithiocarbamate calix[4]arene on Ag nanoparticles and its application in the fabrication of surface-enhanced Raman scattering based nanosensors.

The absorption and self-assembly of a dithiocarbamate calix[4]arene derivative (DTCX) on Ag nanoparticles (NPs) was characterized in this work by surface-enhanced Raman scattering (SERS). This study was carried out on Ag NPs prepared by chemical reduction of silver nitrate with two different reducing agents: sodium citrate or hydroxylamine hydrochloride. SERS was able to discriminate between the different conformations and interaction geometries adopted by DTCX when adsorbed and self-assembled on Ag NPs at different surface coverings. The identification of structural marker bands was crucial in this study. Furthermore, the structure adopted by DTCX is important to determine the activity of this calixarene as a molecular host to detect pollutants, such as pyrene (PYR), since an excessively open or closed cavity is not efficient regarding the analyte detection.