Enhanced luminescent properties of carbon quantum dots on thermo-responsive vinylcaprolactam hydrogel matrix

This research consistsof the preparation and luminescence assessment of hybrid materials made by mixing carbon quantum dots (CQDs) obtained, by a hydrothermal process, from avocado seeds, and vinyl caprolactam (VCL) based thermo-responsive hydrogels. These hydrogels were made by aqueous emulsion homo polymerization of VCL or by the copolymerization of VCL with polyethylene glycol diacrylate (PEGDA), as crosslinking agent. The hybrid materials, hydrogels and CQDs were characterized by FTIR, Raman and XPS spectroscopies and to determine the particle sizes of the different obtained materials either High Resolution Transmission Electron Microscopy (HR-TEM) or Dynamic Light Scattering (DLS) were used. It was found that the combination of the VCL based hydrogels with carbon dots causes an enhancement on the photoluminescence when compared with the bare CQDs. Moreover, an increase in the crosslinking degree of the hydrogel polymeric gel corresponded to more enhancement in the photoluminescence intensity of the hybrid materials. The aforementioned luminescent performance and the biocompatible properties of its components position these materials as potential biomedical thermo-responsive sensors