CdTe quantum dots modified fluorescent polymer microspheres by self-assembly

Abstract

Fluorescent CdTe quantum dots (QDs) modified polymer microspheres with different functional groups were prepared by self-assembly between the carboxyl of 3-mercaptopropionic acid (MPA) on the surface of QDs and basic functional groups (4-vinylpyridine (VPy), N-isopropylacrylamide (NIPAM) or acrylamide (AAM)) of the microspheres. 10 nm of CdTe QDs in diameters were prepared in aqueous solution when 3-mercaptopropionic acid (MPA) was as stabilizer, while functional polymeric microspheres were prepared by distillation-precipitation polymerization when divinylbenzene80 (DVB) was as crosslinker. The TEM results indicated that the microspheres were about 800 nm in diameters and the TEM and fluorescence spectra of QDs conjugated microspheres confirmed that the QDs were self-assembled on the surface of microspheres. The stability of QDs modified microspheres in different pH indicated that the QDs were cut off from poly(VPy-co-DVB) microspheres when the pH was 13, while the cleavage condition of poly(AAM-co-DVB) and poly(NIPAN-co-DVB) were 11 and 9–10 respectively, which indicated that the self-assembly of QDs and poly(VPy-co-DVB) microspheres had the highest stability.