Based on previous data, we have seen a reduction in pore size and porosity when we increase the oxide thickness. For this experiment, we compare asymmetrical oxide thicknesses with symmetrical oxide thicknesses to observe which layer has the dominate effect on pore size and porosity. Wafer 718 is a 40/15/40, 719 is a 20/15/20 and…

To follow up on some of Dave’s work – I was curious if the ALD alumina affects the strength of pnc-Si membranes. Punchline: 2.5 nm of Alumina seems to increase the burst pressure, while 5.0 nm reduces the burst pressure. Methods: As part of routine QC, we had already measured robustness on 6 SepCons to…

This week, I did a systematic study on the growth rate of carbon on bare and aluminum oxide coated pnc-Si membranes. The bare samples were not treated prior to carbonization, while the alumina coated samples underwent a 5 nm treatment in the ALD tool. A bare and alumina coated sample were placed together inside the…

I am trying to deposit metal on the membrane with minimal deposition inside the pores. The image below is an example of how the film quality and thickness change when the sample is positioned at different angles and distances from the source in the same deposition run. The schematic in the corner of each SEM…

For the charge model, we would like to know the surface charge density and size of our experimental molecules.  I’ve attempted to use the Zetasizer for both measurements, but as mentioned in my diffusion paper, DLS gives sizes that deviate from the expected or crystal sizes.  Since zeta potential measurements require large amounts of highly…

I recently performed an experimental separation with 4 proteins in 100 and 10 mM KCl.  All proteins are negatively charged at the pH of the experiments, and we would expect that less would pass through the membrane in the 10 mM KCl solution.  Here’s the gel: You can see that the beta-gal in particular does…

With some of the recent high porosity membranes being produced, I wanted to demonstrate that we can use ALD to create a movable cut-off without sacrificing too much in permeability. I took sc713 and coated it with 5 nm and 10 nm of Al2O3 i.e. I shrank the pore diameter by 5 and 10 nm….

I’ve been working with the AFM recently and have had some success getting images on supported pnc-Si films. Yesterday, I imaged three samples from sc 698: one untreated pnc-Si film and two films coated with aluminum oxide (1.5 nm and 5 nm thickness). Here are the scans (500 nm x 500 nm). The topmost scan…

Today, I ran a quick experiment to confirm that water transport was not negatively affected by an aluminum oxide coating. I deposited 1.5 nm of Al2O3 onto a pnc-Si membrane which I then treated with an oxygen plasma in the YES system. I was curious to see whether the alumina coating along with O2 treatment…

Today while I was imaging a Al2O3 coated pnc-Si membrane on the high-res TEM, I noticed something curious as I placed the beam on a single pore for a few minutes. I was initially interested in the structure of the aluminum oxide coating, but found that something started to deposit on the pore walls as…