Morphological Transformation between Orthogonal Dynamic Covalent Self‐Assembly of Imine‐Boroxine Hybrid Polymer Nanocapsules and Thin Films via Linker Exchange

Abstract

Orthogonal dynamic covalent self‐assembly is used as a facile method for constructing polymer hollow nanocapsules (NCs) and thin films. The bifunctional precursor 4‐formylphenylboronic acid is symmetrically installed with a boronic acid group for the boroxine linkage, and an aldehyde group for the Schiff base reaction which can react with twofold symmetry linkers ethylenediamine and para phenylenediamine to attain polymer NCs and nanosheets. Owing to the reversibility of the imine linkages, the mutual morphological transformation between polymer NCs and thin films via an amine‐imine‐exchange strategy is successfully achieved. Multiple reversible covalent bonds allow the control the release of the load in polymer NCs using different techniques. This may be useful for designing stimulus‐responsive smart materials.

Molecular control over vitrimer-like mechanics – tuneable dynamic motifs based on the Hammett equation in polyimine materials

“…Dynamic covalent (DC) bonds, which combine chemical strength with reversible formation under conditions of equilibrium control, 1 have gained a tremendous interest in several sub-disciplines of chemistry, such as in self-assembly of macromolecular architectures, reversible formation of molecular cages and containers, and in the design of molecular motors. [1][2][3][4][5][6] In recent years, DC chemistry has also become an important tool for the development of new 'smart' polymer materials that are, for example, renewable, self-healing, reprocessable or shape transformable. [7][8][9][10][11][12][13] When DC bonds are included into crosslinked polymeric materials, covalent adaptable networks (CANs) can be synthesised.…”

Template-Free Self-Assembly of Two-Dimensional Polymers into Nano/Microstructured Materials

“…Due to the excellent optical properties, the high emission polymer films showed considerable potential applications in the field of organic photoelectrics. In the subsequent study, Liu and co-workers succeeded in constructing 2D polymer films with an orthogonal reaction of boric acid dehydration and Schiff’s base reaction ( Figure 5 d) [ 54 ]. In experiments, the precursor 4-formylphenylboronic acid was firstly used to construct the boroxine building blocks, which were then polymerized with the para-phenylenediamine linkers to form the 2D polymer film structure.…”

“…Reprinted with permission [ 52 ] Copyright 2013 American Chemical Society; ( d ) Morphological transformation between imine-boroxine hybrid polymer capsules and films and Eosin Y release under stimulation. Reprinted with permission [ 54 ] Copyright 2020 Wiley-VCH.…”

Hollow Polymer Capsules for Drug Delivery

“…Recently, Liu et al [14] developed a new idea to fabricate 2D nanom aterials based on orthogona l dynamic covalent self-assembly by preparing symmetrical building blocks with boroxane connections using 4-formylphenylboronic acid symmetrical connections and performing Schiff base reactions between flexible linkers with dual amino ends and building blocks (Figure 2). Through the dynamic chemistry of Schiff base, a kinetic transformation of the hollow nanocapsule/ nanosheet under different diaminoterminal linker cross-linking was achieved.…”