One-shot preparation of topologically chimeric nanofibers via a gradient supramolecular copolymerization

Abstract

Supramolecular polymers have emerged in the last decade as highly accessible polymeric nanomaterials. An important step toward finely designed nanomaterials with versatile functions, such as those of natural proteins, is intricate topological control over their main chains. Herein, we report the facile one-shot preparation of supramolecular copolymers involving segregated secondary structures. By cooling non-polar solutions containing two monomers that individually afford helically folded and linearly extended secondary structures, we obtain unique nanofibers with coexisting distinct secondary structures. A spectroscopic analysis of the formation process of such topologically chimeric fibers reveals that the monomer composition varies gradually during the polymerization due to the formation of heteromeric hydrogen-bonded intermediates. We further demonstrate the folding of these chimeric fibers by light-induced deformation of the linearly extended segments.

Living supramolecular polymerization of fluorinated cyclohexanes

“…While there has been remarkable progress recently with preparing supramolecular block copolymers under thermodynamic control [60][61][62] or by slow cooling of monomer mixtures [63][64][65] , a growing number of such precision polymers has been prepared by LSP, which can provide superior structural and sequence control. However to date, these LSP approaches either rely on the modification of the polymerizable core, e.g., substituents are attached to the core of rylene dyes 16,66 or the complexation of different metal ions to identical ligands 67,68 .…”

Recent progress and future challenges in the supramolecular polymerization of metal-containing monomers

“…Yagai and co-workers demonstrated the formation of concentric toroids as the starting point for secondary nucleation events. [78][79][80] Based on the specific size of these toroids, the nucleation process led to the formation of polycatenanes, unique hierarchical structures that had remained previously elusive at the supramolecular level. Another highly relevant recent example in this regard is a family of Zn II porphyrin based complexes reported by the groups of Takeuchi and Sugiyasu (Figure 8).…”

Non‐uniform Photoinduced Unfolding of Supramolecular Polymers Leading to Topological Block Nanofibers

“…In fact, while several groups have recently reported elegant examples of block or blocky SPs based on thermodynamic [5] or kinetic approaches, [6] all of them have one‐dimensionally extended structures. As an exceptional example, we recently reported block supramolecular copolymers consisting of helically folded extended domains by kinetically controlled gradient supramolecular copolymerization of the two molecules with similar chemical structures but affording SPs with distinct higher order structures [7] . However, bottom‐up design of such topological block SPs remains a formidable challenge from the viewpoint of the above compatibility between higher‐order structures and hetero‐recognition, which will limit monomer design to those leading to analogous one‐dimensional structures.…”