Organic two-dimensional (2D) nanomaterials are promising candidates in many applications due to their unique architecture and distinctive properties. (Nat. Mater. 2017, 16, 481; J. Am. Chem. Soc. 2017, 139, 9221) However, the 2D structures prepared via crystallization-driven self-assembly (CDSA) usually have a high aspect ratio and a sharp edge. Manipulating 2D disklike nanostructures through new assembly strategies is still challenging. The emerging liquid-crystallization-driven self-assembly (LCDSA) method shows unique mechanisms and good controllability. It is still unknown whether LCDSA can be extended to the 2D growth process of nanoassemblies.
Recently, Professor Jiaping Lin and his colleagues reported a new strategy to realize the controllable fusion growth of 2D disklike micelles of polypeptide block copolymers via LCDSA. Poly(γ-benzyl L-glutamate)-block-poly(ethylene glycol) (PBLG-b-PEG) rod-coil block copolymers first assemble into 2D disklike micelles seeds. By adding unimers into the solution of PBLG-b-PEG disklike micelles seeds, the epitaxial growth behavior is realized. Besides, concentric disklike micelles were obtained (Fig. 1).
Fig 1. Controllable fusion growth of disklike micelles of polypeptides and the concentric disklike micelles.
Combining the experimental observations and theoretical simulations, the mechanism of the chain rearrangement of the PBLG blocks in the 2D disklike micelles is further explained. During the growth, the copolymers first assemble into small aggregates, and the aggregates subsequently fuse with the seed edges. The rod blocks in the aggregates undergo chain rearrangement during the fusion process to match the smectic LC-like structure of the disklike seeds. Finally, the size-controllable concentric disklike micelles were obtained (Fig. 2). It is reported that the rearrangement of the smectic blocks is crucial in controllable growth, which is one of the unique characteristics of LCDSA.
Fig. 2 Liquid-crystallization-driven self-assembly of polypeptides block copolymers into 2D disklike nanostructures
By using the LC driving force and the ability to rearrange the blocks, this work succeeds in controllable fusion growth of the 2D disklike micelles via LCDSA and extends the LCDSA from 1D to 2D, which can address the challenge of the precise manipulation of the 2D nanostructures. The relevant paper is published on Macromolecules. Xiao Jin and Chengyan Zhang of the East China University of Science and Technology are the first authors of the paper. Professor Jiaping Lin and Liang Gao are the corresponding authors.
Macromolecules 2022, 55, 10
Publication Date: May 4, 2022
https://doi.org/10.1021/acs.macromol.2c00581
Copyright © 2022 American Chemical Society
https://pubs.acs.org/doi/full/10.1021/acs.macromol.2c00581