Spraying modes in coaxial jet electrospray with outer driving liquid

Abstract

Coaxial jet electrospray is a technique to generate microencapsules, which uses electric forces to create a coaxial microjet from two immiscible liquids. Compound droplets with narrow size distribution are produced after the jet breaks up. In this paper, the spraying modes are investigated experimentally with proper flow rates of the inner and outer liquids. Ethanol/glycerol/tween mixture ͑outer liquid͒ and cooking oil ͑inner liquid͒ are fed into the gap between outer and inner capillaries and the inner capillary, respectively. The spraying modes presented in our experiments are "dripping mode," "dripping mode in spindle," "cone-jet mode," "pulse mode in cone," and "multijets mode" sequentially, as the applied voltage increases. The region of stable cone-jet mode extends with decrease of the outer liquid flow rate and increase of the inner one. It is found that the spray phenomena are mainly determined by properties of the outer liquid, which is viscous and electric conductive enough. A rudimentary physical model is developed, in which both the viscosity and liquid interface tension are taken into account.

One‐Step Immobilization of Protein‐Encapsulated Core/Shell Particles onto Nanofibers

“…Indeed, the solubility effect was observed in previous results, such as coaxial electrospinning or immiscible coaxial flowing of microfluids, where water soluble organic solvents were used with aqueous solutions. [2,[36][37][38] The flow structure of immiscible two component fluids has a considerable effect on the structure of solidified core/ shell particles, which is related to the protein release profiles. The core/shell structure was observed by a confocal microscope using red/green dyes for the inner/outer solutions, respectively.…”

PEG/PLA core/shell particles from coaxial electrohydrodynamic spray drying

“…19 In addition, core/shell particles have been prepared using two coaxially aligned nozzles. [20][21][22][23][24][25][26][27] However, the commercialization of this technique is hindered by its fairly low production yield, which is limited by the electrohydrodynamic force.…”

Multi-Jet Mode Electrospray for Non-Conducting Fluids Using Two Fluids and a Coaxial Grooved Nozzle

“…Coaxial nozzles have been widely used in the field of micro encapsulation (Chen et al 2005;Xie et al 2008;Kim and Kim 2010), where the two liquids are separately fed into the composite nozzle. In this study, in order to achieve stable multi-jet operation, we used a grooved inner nozzle, where the electric field is enhanced at the grooves (Duby et al 2006).…”