Aggregates of amphiphilic fluorinated copolymers and their encapsulating and unloading homopolymer behaviors

Amphiphilic fluorinated block copolymers synthesized via reversible addition-fragmentation chain transfer polymerization were used for the preparation of aggregates of various morphologies. First, dissolve the copolymer in 2-butanone; second, add a precipitant solvent, which was the mixture of water and methanol, to induce the aggregation of the hydrophobic fluorinated block. With a hydrophilic tail and a very hydrophobic segment, these copolymers are likely to self-assemble in solution and form aggregates. Observed by TEM, spheres, rods, and vesicles can be formed by changing the precipitant mixture contents. Besides, these aggregates were found to be able to carry hydrophobic fluorinated homopolymers, and two suggested processes have been proposed to explain their morphology changes from original spheres, rods and vesicles into larger size spheres. Finally, hollow bilayer spheres and tubules can be achieved after extracting homopolymers in the center of the newly formed spheres. (c) 2008 Wiley Periodicals, Inc.