Synthesis of highly monodisperse quantum dot-loaded polymer beads by impregnation and precipitation techniques



A novel approach to the synthesis of highly monodisperse quantum dot-loaded polymer beads by combining impregnation and precipitation techniques was reported. The monodisperse poly(glycidyl methacrylate) (PGMA) beads were first synthesized by dispersion polymerization. Then, the PGMA beads were chemically modified to generate carboxyl groups, and impregnation of cadmium ions (Cd2+) inside the beads. Subsequently, the cadmium ions were reacted with thioacetamide to form cadmium sulfide (CdS) quantum dots within the polymer beads. The morphology, structure, and properties of CdS quantum dot-loaded polymer beads were studied by field emission scanning electron microscope (SEM), transmission electron microscope, fluorescence spectrophotometer, fluorescence microscope, Fourier transform infrared spectroscopy, powder X-ray diffraction, and thermogravimetric analysis. The results indicated that the CdS quantum dot-loaded polymer beads had an average size of 1.4 μm, and were highly monodisperse. More interestingly, the CdS quantum dots distributed evenly within the polymer beads, which provide very strong fluorescence intensity. The existence of carboxyl groups on the quantum dot-loaded polymer beads was measured quantitatively, and was found to be 0.2 mmol/g. These CdS quantum dot-loaded polymer beads involving functional carboxyl groups would have potential applications in biological immunoassay and photoelectronic fields. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013