I wanted to update everyone on the recent attempts at the formation of the a closed flow system by bonding PDMS to our membrane chips, using capillary tubing for the inlet and outlets. Last week when we tried to preform the UV Ozone bonding it was unsuccessful. I initially thought the bonding did not occur…
Jess showed me how to use the diffusion chamber to separate proteins on the membranes. I ran a gel to see if any proteins appeared in the filtrate. The gel is posted below: The lanes are (from left): protein standard, control, retentate 1, filtrate 1, retentate 2, filtrate 2. It appears that protein diffused through…
In continuation of the desalting work, I ran three additional controls: a SepCon with no slits (negative control) and direct addition of 4M NaCl producing final dilutions of 1:400 and 1:600 (these are the experimental final dilutions I have been working with). The results are shown below. I also calculated the flux for each condition….
I used the spectroscopic ellipsometer to measure several wafers deposited using the AJA system. I verified film uniformity as well as film quality using index of refraction as the metric. The term “w/ Bias” refers to an applied RF power over the substrate. The bias adds energy to the surface as adatoms re-arrange during deposition…
At Nanotech I met a professor from Geneseo, K. Yokoyama, who worked with gold in sol-gels. He found he was able to dissolved gold in sodium tetra bromate (Na2Br4O7) without it aggregating. I have attempted to dissolve gold in other salts to no avail. This is an important step in testing membrane separations with gold,…
I was having trouble using the spectrometer to measure rhodamine concentration in the stir cell. I ran a standardized absorbency of the serial dilution of rhodamine. The curve is posted below. It appears to be linear. The molarity of rhodamine must be above 2uM in order for the spectrometer to read it. I think I…
Chris and I visited the AJA sputter company in Boston last week. The tool was fully functional and we were able to deposit several test wafers. Overall, we were impressed with the performance. The uniformity across a 6″ substrate was sub-1 %. This is certainly a huge improvement over the 3-5% uniformity we currently achieve…
This week I went back and took a look at this figure. In the previous incarnation, when prewetted, PES dropped down in adsorption much less than cellulose. I decided to retry this sample and keep in mind some of the things we have learned since then. I was careful to expose both sides of the…
I recently received wafer 567 from Dave for cell culture work. It has many intact membranes but is riddled with pinholes, having only 3 pinhole-free samples. I decided to test them for air permeability and burst pressure, shown below. I also noticed some odd features on the membrane and surrounding Si. They are circular but…
Lingyun and I used the stir cell and spectrometer to measure the diffusion of rhodamine across the membrane. This was the first time I was able to construct an experiment in the stir cell while keeping both membranes intact. In the past one membrane would rupture or the cell would leak too much. For this…