Synthesis and characterization of self-associative perfluoroalkyl-end-capped polystyrene

Abstract

Polystyrene bearing a perfluoroalkyl group at one polymer chain end was synthesized by a "living" radical polymerization of styrene in the presence of 4-perfluoro(n-tetradecanoylamino)-2, 2, 6, 6-tetramethylpiperidinyl-1-oxy. The "living" polymerization was evidenced by the fact that chain extension occurred upon addition of styrene to a prepolymer at an elevated temperature, i.e., the number-average molecular weight increased linearly with monomer conversion while the molecular weight distribution remained narrow independent of the conversion. The presence of the perfluoroalkyl group in the polymer was confirmed from IR and NMR (1H and 13C) spectra. A preliminary study of the associative behavior of perfluoroalkyl-end-capped polystyrene, using light scattering, spin-lattice relaxation time in 19FNMR, and fluorescence probe techniques, indicated that self-association of terminal perfluoroalkyl groups occurred in benzene at polymer concentrations higher than ca. 30 g L−1 when weight-average molecular weight is as low as 5500.