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Nanofiber processing in microfluidic devices

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.

Archival Publications
Presentations and Other Publications

7-11 Oct 2007

Lok SM, Hinestroza JP, Kirby BJ
"Spatially resolved microfluidic solvent etching of bicomponent extrustion nanofibers", MicroTAS 2007, Paris, France, October 2007.

26 Feb 2007

Kirby BJ
"Design and control of micro/nanoscale fluid systems via polymer synthesis and geometric patterning", Biological and Environmental Engineering Seminar Series, Cornell University, Ithaca, NY.

25 Jan 2007

Kirby BJ
"Design and control of micro/nanoscale fluid systems via polymer synthesis and geometric patterning", Textiles and Apparel Seminar Series, Cornell University, Ithaca, NY.

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.