Week 9

Due to the variables of the electrospinning and the percentages of chemicals used, the fibers could not be tested using the tensile tester created, or a Kawabata machine.  Because they could not be tested, a Scanning Electron microscope was used instead to take a look at the fibers.  After the fibers were created and dried, high magnification pictures were taken using a scanning electron microscope, or SEM. The SEM works by using electrons and x-rays to make a picture instead of using light. The item is put in a vacuum and then an electron beam is shot at the item. When the electron beam strikes the item, electrons and x-rays are released. A detector then captures these electrons and x-rays; they are converted and then displayed as an image. There are many advantages that a SEM has over a light microscope. The SEM can have more items in focus than a light microscope. It also has a higher resolution for clearer and higher quality photos, so that some of the smallest items can still be seen clearly [5]. After the images were created and saved, they were loaded into a program called ImageJ, a program designed to count the number of fibers in an image. The number of fibers were counted and
recorded.

Figure #1: O% Carbon Black and 5%PEO

The sample with 0% carbon black (CB) and 5% PEO spun well.  It had many fibers and the white mat was thick enough to work with it. The ambient conditions benefitted the experiment. The range of the diameter is from .115 to .335 micrometers and the average diameter is .230 micrometers. It was spun at 22% humidity and 23ᵒC. When peeling off the mat it was very easy to remove the foil from the back of it.

Figure #2: 1% Carbon Black and 5%PEO

The second sample, 1% CB and 5% PEO, also spun well.  It had many fibers that had a larger diameter than the basic PEO fibers. The white mat was also thick enough. The range of the diameter is from .199 to .464 micrometers and the average diameter is .262 micrometers. This mat was easy to remove from the foil but a little bit stickier than the first sample.  For this second sample, the humidity was xxx and the temperature was xxx.  

Figure #3: 3% Carbon Black and 5%PEO

The results were the same for the third sample, 3% CB and 5% PEO.  For the third one, the humidity was 21% and the temperature 23. These conditions proved very good because when peeling off the mat it was very easy and the fiber was very thick. This percentage yielded the largest diameter and most fibers. The range of the diameter is from .210 to .547 micrometers and the average diameter is .305 micrometers.

Figure #4: 6% Carbon Black and 5%PEO

The fourth sample that was spun; 6% CB and 5% did work but it did not have a lot of fibers as the other ones. This is because the ambient conditions; humidity 38% and temperature 23 were not favorable. The range of the diameter is from .151 to .377 micrometers and the average diameter is .249 micrometers.

The last sample with 9% CB and 5% PEO did not spin correctly.  This was due to the size of the needle being too small to allow the solution to flow out of it. Furthermore, the solution was too viscous for the electrospinning to work.