Nanoparticle-Decorated Honeycomb-Structured Polymeric Films Via Breath Figures with Janus Particles

The breath figures (BFs) patterning technique represents a simple, robust method for producing microstructured honeycomb-patterned porous polymer films.  Nanoparticles can self-assemble by spontaneous adsorption onto the interfaces between the templating water droplets and the polymer solvent in order to achieve controlled micrometer and nanometer scale hierarchical structures.  Amphiphilic “Janus” nanoparticles were expected to optimize the films with regards to nanoparticle enrichment in the pore walls as well as ordering degree of the honeycomb structures given their dual role as Pickering emulsion stabilizing agents and as highly effective solid surfactants, providing a significant improvement over what has been achieved using isotropic nanoparticles.  Exposed surfaces of silica particles embedded in spherical wax structures (colloidosomes) were chemically modified to render half of the particle hydrophobic.  A reliable method for producing optimal colloidosome coverage was established.  Upon successful synthesis of amphiphilic Janus particles, most reliably confirmed by a two-phase interface test, they were employed in the BFs templating method for the first time, resulting in regular, porous films with uniform, high nanoparticle density.  Characterization of the films’ morphologies will help draw conclusions on the interfacial behavior and self-assembly performance of the Janus particles, as well as the general mechanism of BFs structure formation.