Synthesis and Characterization of Polystyrene Nanoparticles with Covalently Attached Fluorescent Dye

The half seeded emulsion polymerization method was employed to encapsulate fluorescent dye, bromocresol purple (BCP) in polystyrene nanoparticles (PSN) to produce dye/polymer composite colorants. The aim of this study was to investigate the morphology and chemical properties of PSN and encapsulated BCP/PSN. The BCP dye was incorporated into polystyrene nanoparticles formulated from styrene and polymer matrices (eg; emulsifier, initiator, crosslinker). The size, size distribution and emulsion stability of the prepared nanoparticles was examined using Dynamic Light Scattering (DLS) test. The morphology and functional group identification was characterized using Scanning Electron Microscope (SEM) and Fourier Transform Infra-red (FTIR), respectively. As a result, SEM images showed that synthesized polystyrene particles were spherical in shape. The size of polystyrene particles was ranging between 40 – 60 nm and a slight growth of the particles size was observed after the encapsulation of dye which ranges 60 - 70 nm. The BCP dye was leached out from a sol-gel/PSN coated film after 180 minutes reaction time due to the solubility of BCP dye at higher pH.