Synthesis of Quantum Dot-Tagged Submicrometer Polystyrene Particles by Miniemulsion Polymerization

Abstract

Submicrometer fluorescent polystyrene (PS) particles have been synthesized via miniemulsion polymerization using CdSe/ZnS core-shell quantum dots (QDs). The influence of QD concentration, QD coating (either trioctylphosphine oxide (TOPO)-coated or vinyl-functionalized), and surfactant concentration on the polymerization kinetics and the photoluminescence properties of the prepared particles has been analyzed. Polymerization kinetics were not altered by the presence of QDs, whatever their surface coating. Latexes exhibited particle sizes ranging from 100 to 350 nm, depending on surfactant concentration, and a narrow particle size distribution was obtained in all cases. The fluorescence signal of the particles increased with the number of incorporated TOPO-coated QDs. The slight red shift of the emission maximum was correlated with phase separation between PS and QDs, which occurred during the polymerization, locating the QDs in the vicinity of the particle/water interface. QD-tagged particles displayed higher fluorescence intensity with TOPO-coated QDs compared to those with the vinyl moiety. The obtained fluorescent particles open up new opportunities for a variety of applications in biotechnology.

Os nanomateriais e a descoberta de novos mundos na bancada do químico

“…Apesar de neste caso ocorrer ligação entre os QD e o polímero, ainda se observa migração dos QD para a superfície, o que é acompanhado por uma deterioração da fotoluminescência do material final. 100 De forma a tentar minimizar o efeito de deterioração das propriedades de emissão por fotoluminescência, foi descrito um método em duas etapas que contempla, num primeiro passo, a formação de uma camada de sílica na superfície dos QD, seguido de um processo de copolimerização à superficie. Esta reação de copolimerização ocorre através da funcionalização da superfície de sílica com 3-metacriloxi--propil-trimetoxi-silano (MPTMS) que possui grupos polimerizáveis.…”

From Ruthenium Complexes to Novel Functional Nanocomposites: Development and Perspectives

“…[18] This method was used for various inorganic materials, such as TiO2 [49][50][51] and SiO2, [52] where these were directly dispersed in the monomer. More recently the NP encapsulation by an in situ miniemulsion polymerization was demonstrated with poly-styrene, [53][54][55] poly-butyl acrylate [53,56] and a poly-styrenepoly-methylmetacrylate copolymer. [57] However changes in the crystallization of semicrystalline polymer matrices in nanocomposites has also been described.…”

From polymeric particles to multifunctional nanocapsules for biomedical applications using the miniemulsion process

“…CdS or CdSe QDs hydrophobized by trioctylphosphine oxide allows the direct dispersion of the QDs in the monomer and a subsequent miniemulsion polymerization procedure. Hybrid particles with PS [120][121][122] or PBA particles 121,123 could be prepared, which show good photoluminescent properties. Also CdTe, stabilized by 3-mercaptopropionic acid could be homogenously incorporated in PS nanoparticles using octadecyl-pvinylbenzyldimethylammonium chloride or didecyl-p-vinylbenzylmethylammonium chloride as phase-transfer agent.…”