Polyfluorene polyelectrolyte nanoparticles: synthesis of innovative stabilizers for heterophase polymerization

Polyfluorene-bearing bromohexyl side chains are quaternized by 1-vinylimidazole in order to attach dialkylimidazolium bromide ionic liquid (IL) species along the conjugated backbone. Subsequently, polyfluorene polyelectrolyte nanoparticles (NPs) of 40 nm in average size are created via radical cross-linking of the pendant vinylimidazolium groups. Anion exchange from Br(-) to BF(4)(-), PF(6)(-), and bis(trifluoromethylsulfonyl)imide anion (TFSI(-) renders NPs adjustable dispersability in various organic solvents. The hydrophobic-conjugated backbone and the hydrophilic dialkylimidazolium bromide IL moieties depict an amphiphilic profile, which allows the NPs to be deployed as conductive stabilizer in the emulsion polymerization of styrene. The resultant latexes are fluorescent, tunable in size and can be transferred to organic solvents without forfeiting their colloidal stability.