Fluorescence to study aggregation of amphiphilic copolymers in aqueous media

Random copolymers of 3-hexadecyl-1-vinylimidazolium bromide and N-vinyl-2-pyrrolidinone were synthesized by free radical copolymerization at various feed compositions. These copolymers, whose structure was determined by ¹³C NMR spectrometry, self-aggregate in aqueous media. The formation of the resulting hydrophobic microdomains was analyzed by spectrofluorimetry, using pyrene and a molecular rotor as fluorescent tracers. The results are discussed in relation to the molecular structure of the copolymers, particularly for the case of the micro cohesion sensed by the molecular rotor.