ฉันรักการอ่านThe solutions used in the electrospinning experiments
were prepared using 400,000 molecular weight Poly(ethylene
oxide) (PEO) purchased from Scientific Polymer
Products. This material was dissolved in HPLC grade
water to make solutions with concentrations ranging from
4 to 10 wt%. Surface tensions for each solution were determined
by the Wilhelmy Balance method using glass microscope
cover slides that were cleaned with a butane torch.
Solution viscosities were measured with a TA Instruments
AR 1000-N constant stress rheometer in a cone and plate
geometry. Each experiment was performed at 208C with a
4 cm and 28 cone. Solutions were spun from a 50 ml syringe
with a 23 gauge (diameter 0.35 mm) needle. A Gamma
High Voltage Research ES30P power supply was used to
produce voltages ranging from 5.5–15.0 kV. Various electrically
grounded materials, such as aluminum screen, were
used as targets.