Shengqing Xu

Microfluidic consecutive flow-focusing droplet generators

This article describes emulsification in a microfluidic double droplet generator (DDR) comprising two consecutive flow-focusing devices with locally modified surface chemistry. We generated W/O/W, O/O/W and O/W/O double emulsions with precisely controlled sizes and morphology of droplets. Secondly, by combining two mechanisms of droplet formation (the flow-focusing mechanism and the break up of liquid threads at T-junction) we produced multiple populations of droplets with varying size and/or composition. These droplets were used as the structural units for the formation of complex dynamic lattices.

Hybrid polymer-inorganic materials: multiscale hierarchy

The paper describes a new approach to producing hybrid composite materials with multiscale morphologies. We doped polymer submicrometer spheres with semiconductor or metal (CdS or Ag, respectively) nanoparticles and used these doped microspheres as the functional building blocks in production of hybrid periodically structured materials. The preparation of hybrid polymer particles included the following stages: (i) synthesis of monodisperse polymer microspheres, (ii) in situ synthesis of the inorganic nanoparticles either on the surface, or in the bulk of the polymer beads, and (iii) encapsulation of hybrid microspheres with a hydrophobic shell. We demonstrated that by changing the composition of the polymer beads good control could be achieved over the size of the nanoparticles.