Electrospinning first mat

On Wednesday, April 25, the group was able to produce the first nano-fibrous mat sample in the lab. Aided by the group advisor, Marjorie Austero, we gained experience with the electrospinning equipment and working in a lab environment. Conditions in the lab prohibited spinning under our predetermined parameters. Critical factors like solution composition, solution flow rate, and collection plate distance had to be re-evaluated before a consistent production of fibers was attained. The following chart contains the predetermined conditions, as well as the actual experimental conditions that successfully produced fibers.

Lab Parameters and Conditions
Parameter	Predetermined	Experiment 1
Solution Composition	5% PEO 500,000	3% PEO 900,000
Flow Rate	0.2 mL/hr	0.5 mL/hr
Needle Diameter	0.6mm	14.5mm
Voltage	15 kV	15 kV
Collection Distance	20 cm	11 cm
Time Spinning	est. 3-5 hrs	3 hours
Independent Parameters
Air Temperature		22.8 C
Humidity		22%

(Table 1- The table contains the theoretical parameters determined before working in the lab, as well as actual conditions experienced during experimentation.)

The theoretical parameters chosen were based upon a study that analyzed various components of PEO in water. One major difference between the study and our experiment was the ambient humidity. In the study, testing took place in 50% relative humidity, whereas in our lab, the humidity was much lower at 22%. Because humidity was very low, and the needle diameter was much larger than intended, the theoretical conditions prepared did not successfully spin fibers.

In order to compensate for unexpected lab conditions, the solution was changed to a heavier polymer at a lower concentration. In addition, the flow rate and collection distance had to be adapted before fibers could be generated. Under these conditions, a nanofiber mat was produced after 3 hours time spinning. The mat will be prepared for observation under the scanning electron microscope (SEM) in the beginning of next week. Once the SEM imaging is obtained, analysis of fiber diameter and pore size of the mat can occur. With this information, the spinning parameters again be adapted to further optimize the filtration properties for the next mat we create.