Microdenier fibers have been produced via bicomponent
extrusion of a desired polymer and a
soluble or sacrificial polymer for more
than 30 years. The use of spin-packs allows
for the production of uniform domains with
diameters as small as 500 nanometers. However,
when the dimensions of the nanodomains are in the
order of tens of nanometers, several unusual
flow phenomena occur, including domain encapsulation, domain
coalescence, domain dimensional instabilities,
differential crystallization kinetics, and induced
superdrawing.
In collaboration with
Juan Hinestroza in Cornell’s
Fiber Science and Apparel Design department,
we are using flow focusing in glass microfluidic
substrates to solvent-etch composite fibers with
micrometer resolution.
Atomic-force acoustic microscopy methods and three-point
bending using atomic force microscopy tips are
used to measure the mechanical properties of
individual nanofibers.
Publications and Presentations on Nanofiber Processing
Lok SM,
Hinestroza JP,
Kirby BJ
"Spatially resolved microfluidic solvent etching of bicomponent
extrustion nanofibers",
MicroTAS 2007, Paris, France, October 2007.
Atomic-force microscopy image of
a polyester/polyethylene fiber containing
1120 nanodomains and showing domain
coalescence and domain dimensional
instabilities, particularly in the outward
radial direction (courtesy
J. Hinestroza). We are using microfluidic techniques to pattern micron-scale
portions of these nanofibers for material characterization.
An image of a composite microfiber with nanoscale domains
that has been inserted into a glass microfluidic devices for spatially-
resolved solvent processing. The materials properties of the resulting
exposed nanofibers can be characterized using AFM techniques.
An image (using polarization microscopy) of a
composite microfiber with nanoscale domains
that has been inserted into a glass microfluidic devices for spatially-
resolved solvent processing. Field of view is approximately 300 microns.
The materials properties of the resulting
exposed nanofibers can be characterized using AFM techniques.
Microfluidics/Nanofluidics Laboratory, 282 Grumman Hall, Cornell University, Ithaca, NY 14853 email webmaster with comments/corrections/questions
