Solvothermal synthesis of polyazomethine microspheres by Pickering emulsion templates and their transformation into complex microtubes and anisotropic hollow spheres enabled by dynamic imine chemistry

Dynamic covalent chemistry has attracted much attention in recent decades. Here we report a facile one-pot solvothermal synthesis of anisotropic polyazomethine particles using Pickering emulsions formed in situ as templates. An unexpected morphological transformation from nanoparticles to anisotropic particles and finally to complex anisotropic yolk-shell structures was observed. The underlying mechanism is a controlled chemical etching process enabled by the dynamic imine bonding and the inhomogeneous nature of the resulting anisotropic particles. The generalizability of this process was further proved by fine tuning the initial solvent composition, through which an interesting morphological transformation from hollow spheres to wormlike tubes and finally to microtubes with a smooth surface was observed, thus providing a novel template-free strategy for the synthesis of polymeric materials with complex hollow interiors, which has rarely been reported in polymeric systems.