Toroid Formation through a Supramolecular Cyclization Reaction of Rodlike Micelles

Constructing polymeric toroids with a uniform, tunable size is challenging. Reported herein is the formation of uniform toroids from poly(gamma-benzyl-l-glutamate)-graft-poly(ethylene glycol) (PBLG-gamma-PEG) graft copolymers by a twostep self-assembly process. In the first step, uniform rodlike micelles are prepared by dialyzing the polymer dissolved in tetrahydrofuran (THF)/N, N'-dimethylformamide (DMF) against water. With the addition of THF in the second step, the rodlike micelles curve and then close end-to-end to form uniform toroids, which resemble a cyclization reaction.