A new spin on an old technology will give scientists and manufacturers the
ability to significantly increase their production of nanofibers, according to
researchers at North Carolina
Collections of nanofibers, because they are porous and lightweight, are
useful in applications ranging from water filtration to tissue regeneration to
energy storage. But although nanofibers are relatively inexpensive to produce,
the current method of production—needle electrospinning—is time-intensive.
In electrospinning, a liquid-polymer solution is passed through a hypodermic
needle held at high voltage. The needle transfers electric charge, which
transforms the solution into a jet of charged liquid that spins into a
nanofiber as it exits the needle. Unfortunately, this method of production does
not lend itself to large-scale manufacturing processes.
NC State physicists Laura Clarke and Jason Bochinski, textile engineer Russell
Gorga, and graduate student Nagarajan Thoppey found a particularly simple
technique that scales up nanofiber production and provides a close connection
to the needle electrospinning method. In a study recently published in Nanotechnology,
they demonstrated bowl electrospinning. In place of a hypodermic needle, the
researchers filled a bowl with the polymer fluid and applied a short burst of
very high voltage to the liquid’s surface, which caused multiple jets to form
and spin nanofibers onto a collector placed around the outside of the bowl.
Bochinski says the experiment gave them a 40-fold increase in nanofiber
production, and demonstrated the potential for further increases. It also led
to one question that they hope to answer in the near future:
“One of our next steps will be studying the limitations of the bowl
apparatus we used—for instance, why was the increase only 40-fold and not
40,000-fold—and how that relates to the geometry of the arrangement and the
fluid’s properties,” Bochinski says.