Polycarbonate track-etched membranes experiments
First experiment was to confirm the official air flow rates data with our setup. The measurements are taken at 10psi (as the ones that company did). The results of these tests are in the graph below. The filled points on the graph are experimental and the empty ones are official rates from the company website.
Second part of experiment was to compare the air permeability of our membranes with TE membranes. These tests are done in the same way and at the same conditions for both membrane types (pressurized at 1 psi). All data is normalized by the area and leakage tests are taken.
Two images below are the air permeability for TE membranes and wafer338.
Here are few numbers from the graphs:
PCTE permeability (cc/cm2-s-atm):
- 0.53 (0.01micron pore diameter),
- 1.57 (0.03micron pore diamater)
pnc- Si w338 permeability (cc/cm2-s-atm) :
- 669.9346 cc/cm2-s-atm (0.019micron mean pore diameter)
This measured permeability data for TE membranes is on the same order as in carbon nanotube membranes paper (graph below).
Also, TE membranes are covered with PVP (Polyvinylpyrrolidone) polymer to make them more hydrophilic and more easily wettable. PVP is very easy to remove using hot water. I tested washed and dried TE membranes for permeability, didn’t see difference from regular ones. Information about PVP is here
This is great! Everything seems to be making sense and we seem to have at least a 100X enhancement over the PCTE membranes at similar pore size.
Is this the expected enhancement factor? What do the model equations predict for the PCTE membranes with the physical characteristics that you mention?
I modeled the molar flow for these TE membranes, it is approximately 100 times lower. It is expected, because the correction factor depending on radius/length becomes much higher.