(615g) Formation of Multi-Nanoemulsions for Colloidal Synthesis

In recent years, complex emulsions – i.e., droplets with internal structure – have generated great research interest due to their potential applications in materials,foods,cosmetics, pharmaceuticals,and chemical separations. Microfluidic methods have already demonstrated the ability to create micron- and larger scale complex emulsions with breathtaking sophistication and control, as well as compartmentalize encapsulation of molecules within them. However, scaling the size of such droplets to the nanoscale has been extremely challenging due to limitations on the devices and energies required to produce nanoscale droplets, i.e. nanoemulsions. Here, we report the ability to fabricate complex nanoemulsions of various morphologies, and use them as templates for nanoparticle synthesis. To produce complex morphologies, we combine high-energy emulsification methods with co-surfactant pairs possessing highly asymmetric molecular geometry. The former aids the generation of nanoscale droplets, whereas the latter influences their morphology through ultra-low surface tension and control over frustrated spontaneous curvature, resulting in the reproducible generation of droplets with a range of controlled complex morphologies. The size, stability, internal morphology and chemical compartmentalization of these complex nanoemulsions have been quantified using a combination of scattering, optical microscopy and cryogenic-transmission electron microscopy techniques. We show that complex droplet morphologies are retained upon the addition of various material pre-cursors, and that the droplets are stable over the time scales required for material chemistry, thereby enabling their use as templates for complex nanoparticles.