Colorful Polyelectrolytes: An Atom Transfer Radical Polymerization Route to Fluorescent Polystyrene Sulfonate

Abstract

A labeled green fluorescent polystyrene sulfonate (LNaPSS) has been synthesized using atom transfer radical polymerization of a styrene sulfonate monomer with a fluorescent co-monomer, fluorescein thiocyanate-vinyl aniline. As a result this 100 % sulfonated polymer contains no hydrophobic patches along the chain backbone besides the fluorescent marker itself. The concentration of the fluorescent monomer was kept low to maintain the characteristic properties of the anionic polyelectrolyte, LNaPSS. ATRP conditions facilitated the production of polymers spanning a range of molecular weights from 35,000 to 175,000 in gram-scale batches with polydispersity indices of 1.01-1.24. Molecular weight increased with the monomer to initiator ratio. Gel permeation chromatography results show a unimodal distribution, and the polymer structure was also confirmed by (1)H NMR and FT-IR spectroscopy. Fluorescence spectroscopy confirmed covalent bonding of fluorescein isothiocyanate to the polymer, indicating that the polymer is suitable as a probe in fluorescence microscopy. To demonstrate this ability, the polymer was used to locate structural features in salt crystals formed during drying, as in the evaporation of sea mist. A second application to probe diffusion studies is also demonstrated.

Synthesis of perfectly sulfonated sodium polystyrene sulfonate over a wide molar mass range via reversible‐deactivation radical polymerization

“…It forms an active complex for ATRP yet remains stable toward disproportionation . The Cu/Bpy system has been previously reported for the synthesis of NaPSS, and has recently been shown to be a relatively stable active catalyst system in an aqueous environment . A higher deactivation rate constant than expected results in narrow molecular weight distributions .…”

“…Iddon et al demonstrated room temperature syntheses of NaPSS in a mixed H 2 O/MeOH solvent, but the molecular weights did not exceed 25,000 g mol −1 and Ð values were high (1.26–2.03) . Huberty et al produced NaPSS via an aqueous ATRP with molecular weights of 30,000–2 × 10 5 g mol −1 and Ð values in the range of 1.01–1.24 but the reaction was reported to lack reproducibility …”