Electrospraying is an electrohydrodynamic technique for the fabrication of uniform micro- and nano-particles. This versatile and inexpensive process shares many of the same principles as for the electrospinning of fibers and both processes can be performed with the Spinbox without any modifications to the apparatus.

Figure 2. Electrospraying process

The key difference between electrospraying and electrospinning is the composition and properties of the solution being processed: low viscosity solutions tend to lead to electrospraying of particles, whereas higher viscosity solutions tend to lead to electrospinning of fibers. In both processes the electrostatic repulsive forces acting on the solution droplet cause the formation of a highly charged jet from the Taylor cone, but in the case of low viscosity solutions that lack the molecular entanglement required to form fibers, surface tension is more dominant and the jet breaks up into droplets. These highly charged droplets break up into smaller and smaller droplets as the solvent evaporates, resulting in the deposition of dry particles onto the grounded or negatively charged collector.

The size of the particles can be controlled by adjusting solution and processing parameters (predominantly solution concentration and flow rate), and crucially electrospraying enables the fabrication of smaller and more uniform particles than other commonly used particle fabrication techniques, all at room temperature.