- Electrospinning is a process which uses high voltage applied to a liquid and a metal collector to draw fibers from said liquid on a microscopic scale for collection onto a mat. These mats have a variety of uses, including artificial cartilage, artificial organ growth, and the creation of long fiber composite materials, but most are limited in application by having a relatively small tensile strength.
- The problem we seek to address is that of creating mats with a larger tensile strength than current designs would allow.
- Any method of increasing tensile strength must be chemical in nature (i.e. a modification to the solution that is being electrospun). Any attempt, with current technology, of strengthening it via physical, macroscopic means (e.g. wrapping the mat in duct tape after its completion) would remove the special properties of the electrospun material.
- Any method of increasing tensile strength must not alter the structure of the nanofibers beyond a point where the fibers cannot be used for their intended application.
- While a very large number of different solutions have been spun and cataloged with a correspondingly large variation in tensile strength, a relatively small amount of work has been done comparing tensile strengths of related material.
- One documented method is to increase the molecular weight of the solution being electrospun, if appropriate. It has been shown that increasing the molecular weight of nylon-6, for instance, can increase the Young's Modulus of the resulting mat by nearly 50% and the tensile strength by more than 125% [1].
- Another documented method is to introduce milled nanodiamonds into the solution being electrospun. This has not currently been successful, since the nanodiamonds have a tendency to clump instead of being evenly dispersed along the fibers and thus minimize any benefit they would have [2].
- A method not yet published is to make a solution, introduce milled nanodiamonds to it, and heat it to attempt to remove some of the water from the solution, in the hopes of allowing the nanodiamonds to evenly disperse with less water to cause surface tension. Preliminary results, however, show that the heating itself may cause nanodiamonds to clump together.
- Our design goal is to find a way of introducing milled nanodiamonds into a solution being electrospun without the nanodiamonds clumping, and to observe whether or not this does increase the tensile strength of the mat.
- The solution used for the baseline testing will be an 20 wt% (weight percent) PAH (polyallylamine) / water, as this is a commonly used and well documented solution.
- Two electrospun mats:
- One with nanodiamonds evenly dispersed throughout the fibers.
- One with no nanodiamonds.
- SEM (Scanning Electron Microscope) and TEM (Tunneling Electron Microscope) images of both mats.
- Tensile strength tests for both mats.
- Week 3: Prepare solution of PAH / UD90 and put in a vacuum pump to remove some of the water from the solution.
- Week 4: Prepare solution of PAH and attempt to spin.
- Week 5: Attempt to spin solution of PAH / UD90.
- Week 6: View resulting mats of PAH / UD90 and PAH under SEM.
- Week 7: Submit mat samples to TEM lab for analysis.
- Week 8: Conduct tensile strength tests on mat samples.
- Week 9: Finalize report.
- Week 10: Give presentation.
Projected Budget
- We expect to either not incur any expenses, or very minor ones, since all of our materials are readily available, and we are using small quantities of them.
Bibliography
- Ojha, Satyajeet S., Mehdi Afshari, Richard Kotek, and Russel E. Gorga. "Morphology of Electrospun Nylon-6 Nanofibers as a Function of Molecular Weight and Processing Parameters." Journal of Applied Polymer Science 108.1 (2008): 308-19. Wiley Online Library. Wiley.com. Web.
- Behler, Kristopher D., Antonella Stravato, Vadym Mochalin, Guzeliya Korneva, Gleb Yushin, and Yury Gogotsi. "Nanodiamond-Polymer Composite Fibers and Coating." ACS NANO 3.2 (2009): 363-69. Web.
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