Cooperative polymerization, aided by the nucleation-elongation mechanism, has the promise of providing polymers and nanostructures that are otherwise inaccessible. The molecular origin of the cooperative growth of polymers is driven by a secondary interaction, often based on polarization, electrostatics, or sterics-driven secondary structure. However, for the first time, we demonstrate that covalent dative interactions between the nitrogen in the imine building blocks and the boron in the boronate ester can be used to achieve cooperative polymerization. Our results suggest that the initial polymer formation through sequential boronate esterification of boronic acids and bifunctional catechols under ambient conditions serves as the nucleus for monodisperse nanoparticle assembly. The dynamic nature of the dative interaction in this equilibrium self-assembly has been shown to endow these nanoparticles with thermal responsive characteristics. Further, we show that a metal ion-induced change in the particle morphology was observed by TEM. Our results suggest that the formation of these hollow metal-organic nanoparticles can be attributed to the Kirkendall effect. We expect that these findings will not only have a considerable impact on the development of supramolecular systems based on cooperative polymerization and dynamic covalent bonds, but also on the development of metal-organic materials.

Polymeric nanoparticles from cooperative polymerization and their dynamic behaviors

249th National Meeting (2015)

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