This is some really preliminary data that I hope to add to in the next couple of days. Yesterday I prepared 4 SepCon samples from wafer 310. I spun them at 3.3 psi for 2 hours with just PBS. I recorded the permeability, and then performed the exact same test with 3mg/mL protein in the…

Using Mike B.’s MATLAB script, I was able to generate some histograms and stats for wafer 187, 310, 319 and 320. I excluded the “small pore background”, as I do not believe these features go all the way through the membrane. wafer 187 wafer 310 wafer 319 wafer 320 The reason why I did not…

I only added coordinates on each data point.

Production this week focused on varying the RTP temperature of membranes deposited under identical conditions. wafer 316 – 800 C RTP (120 s) (0,-5) @ 50 kx Material still appears to be amorphous. Wrinkled at edges. wafer 318 – 900 C RTP (120 s) (0, 0) @ 50kx (-5, 0) @ 50kx A few, very…

These are the graphs with burst pressures for wafers 187, 189, 310, 312 and updated burst pressure bookMembrane_Burst_Book.xls The orange columns in the graphs indicate samples that I used for air permeability tests before.

Below are results for air permeability tests I took on wafers w302, w304, w187, w189, w310. The X axis is the position of a sample on the wafer (from inside to outside).Samples form wafer 189 passed no air and the permeability of wafer 187 is extremely low.Permeability of other wafers increases closer to the outer…

This week I tried to run a few “eq-tests” with some samples from wafer 187 to get some hydraulic permeability value for our membranes to see how they compare to the polymer filters used in the microcon and nanosep systems. Unfortunately I have no results to report, of the two samples I tested one broke…

I’ve been doing some reading, and came across this article by researchers at Sandia Nat’l Labs. They are looking at the stress evolution in thin films, and have observed “nanovoids” in their amorphous silicon. Here is a cross-sectional TEM image (XTEM) from the article. Floro et. al. PRL 2003 There are three layers of a-si…

This week I set up some diffusion experiments with the inner membranes of wafers 187 and 310. From the TEM images posted previously, we see that these inner membranes have what appear to be either very small pores or small divots that do not pass entirely through the membrane. I allowed the protein standards to…

Link to “A closer look at separations” We recently bought purified proteins that I will use to build a molecular weight ladder for membrane separations. I initially dissolved these proteins in salt solution and spun in an ultracentrifuge to remove aggregations. I then sized the proteins using our Malvern Zetasizer, which gives hydrodynamic radius, assuming…