Electrohydrodynamic atomization (EHDA) is a key research area for producing micro and nano-sized structures.
This process can be categorized into two main operating regimes: electrospraying for particle generation and
electrospinning for fibre production. Producing particles/fibres of the desired size or morphology depends on
two main factors; properties of the polymeric solution used and the processing conditions including flow rate,
applied voltage and collection distance. In this work the particle-fibre transition region was analyzed by changing
the polymer concentration of PLGA poly (lactic-co-glycolic acid) in acetone between 2 and 25 wt%. Subsequently
the processing conditions were adjusted to study the optimum transition parameters. Additionally the EHDA
configuration was also modified by adding a metallic plate to observe the deposition area. The diameter and
the distance of the plate from the capillary tip were adjusted to investigate variations in particle and fibre morphologies
as well. It was found that complete transition from particles to fibres occurs at 20 wt% indicating concentration
to be the dominant criterion. Low flow rates yielded fibres without beads. However the applied
voltage and distance between the tip of the nozzle jetting the polymer solution and collector (working distance)
did not yield definitive results. Reducing the collector distance and increasing applied voltages produces smooth
as well as beaded fibres. Addition of a metal plate reduces particle size by ~1 μm; the fibre size increases especially
with increasing plate diameter while bead density and size reduces when the disc is fixed closer to the capillary
tip. Additionally, the deposition area is reduced by 70% and 57% with the addition of metal plates of 30 mm
and 60 mm, respectively. The results indicate that a metal plate can be utilized further to tune the particle/fibre
size and morphology and this also significantly increases the yield of EHDA process which is currently a limitation
in adopting it as a mass production technique.
© 2016 The Authors. Published by Elsevier