Toroid Formation through a Supramolecular “Cyclization Reaction” of Rodlike Micelles

Abstract

Constructing polymeric toroids with a uniform, tunable size is challenging. Reported herein is the formation of uniform toroids from poly(γ-benzyl-l-glutamate)-graft-poly(ethylene glycol) (PBLG-g-PEG) graft copolymers by a two-step 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.

Consequences of a cosolvent on the structure and molecular dynamics of supramolecular polymers in water

“…We expect that an increased understanding on the role of a cosolvent in water, in terms of molecular events, will contribute at a fundamental level to the development of multistep non-covalent synthesis protocols. 50 , 51 Moreover, these insights will be crucial for all assembly studies of molecules in water that use a cosolvent in the assembly process.…”

The Special “Morse Code” between Solvent Polarity and Morphology Flexibility in a POSS–Dendrimer Supramolecular System

“…[34,35] The simulations were performed by applying the simulator,c oarse grained molecular dynamics program based on LAMMPS. [37,38] The integration time step Dt = 0.005t,a nd the simulation temperature k B T = 3.0e were selected, where t was the unit of time in the simulation.…”

“…The integration time step Δ t =0.005 τ , and the simulation temperature k B T =3.0 ϵ were selected, where τ was the unit of time in the simulation. Other Brownian dynamic simulation conditions can be found in our previous work …”

Helical Toroids Self‐Assembled from a Binary System of Polypeptide Homopolymer and its Block Copolymer

“…As the added water content increases, a part of the slender fibril prefers to curve into a loop (Figure b), which is attributed to the change in the interfacial energy between the fibrous aggregates and the solvent. It is known that the formation of closed loops is a free‐energy‐favorable process for fiber‐like structures in a selective solvent . Because of the longer length of the fibrils, it is difficult to form a closed toroid.…”

“…The backbone rigidity was realized by maintaining the angle between two neighboring backbone bonds unchanged. The attractive potential was set for R‐R and P‐P pairwise interactions to describe the hydrophobic nature of PBLG backbones and the π–π interaction between phenyl groups, respectively . The repulsive potential was given for the R‐P interaction .…”