Electrohydrodynamic Atomization Processing Biologically Nanostructured Materials

Abstract

Electrohydrodynamic atomization phenomena has increasingly attracted the attention of researchers who are interested in pursuing this promising technique to prepare microor nanometer architectures such as fibers and encapsulated particles with a controllable microstructure. There are two main techniques in the electrohydrodynamic atomization processing: electrospraying and electrospinning. Electrospraying can create particles by applying a uniform electrohydrodynamic force to break up liquids into fine jets, and is an emerging method for the rapid and high throughput production of nano-meso scale particles of controlled morphology for controlled release during drug delivery. The morphology and size of electrosprayed polymer nanoparticles is strongly influenced by a host of variables that include processing parameters and the material properties of the solution such as polymer composition, molecular weight, the solvent used for polymer dissolution, and the presence and concentration of other cosolutes. In a typical electrospinning process, the precursor solution is held at the end of the nozzle in the form of a droplet by its surface tension. As is the case with electrospraying, a voltage applied to the nozzle results in the formation of a Taylor cone, from which a jet of the precursor solution will erupt. Although the jet in a Taylor-cone mode is stable near to the tip of the nozzle, it undergoes a fluid instability stage that leads to accelerated solidification of the jet and a thinning of the fibers as the jet approaches the collector [1-4] (Figures 1 and 2).