Facile fabrication of monodisperse fluorescent polystyrene composite microspheres

Abstract

Abstract. Fluorescent poly(St-co-Eu(MAA) 3 Phen) microspheres have been facilely fabricated via copolymerization of styrene and Eu(MAA) 3 Phen with using the mixture of water and methanol as the dispersing medium in presence of sodium p-styrenesulfonate (NaSS). Strong photoluminescent europium coordination compound was inherited in the resulting polystyrene composite The microstructures and morphologies 3 Phen) were of the obtained poly(St-co-Eu(MAA)characterized by using FT-IR, SEM-EDS, ICP-MS and TEM. Their fluorescence properties were measured by the fluorescence spectrometer. Introduction Nowadays, luminescent materials have attracted increasing attention. It is supposed to be an effective way to obtain excellent luminescent properties by rare earth doping. Generally, majority of rare earth ions have abundant f-orbital configurations, so there are three types of electronic transition in rare earth complex: f-f transition, f-d transition, and ligand-metal f charge transfer transition. The photophysical properties of rare earth ions such as Eu(III),[1-4]possessing longlived excited states and line-like emission bands, makes these ions as the excellent candidates for the applications such as photoelectric devices, solid state laser, optical data storage, flat plane displays, high energy radiation detectors and so on[5-7]. Moreover, fluorescent microsphere is a typical example, which has been used as fluorescent probes and luminescent labels in chemical, biological systems , and medical diagnostics[8]. To fabricate fluorescent microspheres with rare earth-polymer complexes, there are mainly two chemical routes to embed the metal-containing coordination chromophores covalently to polymeric bodies so as to prevent phase separation and leach photoactive components[9-11]: one is to apply a functional polymer to react with a metal salt and the other is to directly co-polymerize a metal-containing precursor[12, 13]. In ever reports, the resulting ionic aggregates in rare earth-polymer complexes tend to bring about critical emission quenching by the former way due to the fact that polymer chain could be tangled even at low rare earth content,, while the latter method actually offers a well-defined structure around the metal center to lead to explicit optical-physics properties in turn, although the rare earth complexes are not just on the surface. However, there are still some problems in using such rare earth coordination compounds directly, for example-such complexes are insoluble in usual organic solution during polymerization. Here, we present a facile way to fabricate stable fluorescent microsphere via the copolymerization of styrene with Eu(MAA)