Here are the results for air permeability testing of W501. The sample closest to the origin had one very small (very difficult to see on Brian’s scope unless viewing at 100x) pinhole, the middle sample had 3 very small pinholes. The completely intact sample had a permeability of .773 cc/(cm^2*atm*s). It seems that the pinholes…
The unwashed membrane has a definite “film” over it which makes the pores look textured. The MeOH & H2O seems to clear the pores up, but there are some places where there is remaining PVP that sticks to the inside walls of the pore.
This week, we explored the possible differences a thermal oxide making layer had versus a TEOS on membrane morphology. Here’s what we found: The top image shows wafer 410 @ (1,0) and the bottom wafer 503 @ (1,0). Both wafers were annealed, cleaned, sputtered using the same conditions. The only difference was the masking material….
Over the past five days Anant and I monitored human umbilical vein endothelial cell (HUVEC) proliferation on three substrates: RTP-treated Si samples (both with and without membranes), glass (microscope coverslips), and plastic (6-well tissue culture plates). After the first two time points very few cells were observed on the silicon samples, so we added more…
I recently set up 24 hour diffusion separations with the BioRad protein standards. The following gel shows the separations using w415 position (-4,3) and w416 (-1,3). Different cutoffs were observed with the two membranes.
I recently tested intact samples from W415-T and W416-T. All samples from W415-T were completely intact except the one located 3.167 units from center, which had one medium pinhole. All samples from W416-T were intact, but a few had irregular membrane shape, one with constant area and two with about +5% membrane area. I thought…
Tom prepared two PVP coated TEM samples for me to image today. One of the samples was washed with dH20 and the other left untouched. Below is a series of three images, from left to right: no PVP, PVP no wash, PVP & wash. I wasn’t able to tell any differences under the River Campus…
I recalculated the permeability of the track-etched membranes using Poiseuille’s Law this time assuming that the pore diameters specified by Sterlitech are smaller then the actual pore sizes. For the first recalculation I assumed that the “real pores” are 20% larger then specified by Sterlitech. As shown above the resultant Poiseuille’s Law predictions are much…
We’ve recently put together our own protein ladder, which contains myosin heavy chain, beta-galactosidase, phosphorylase b, IgG, albumin, and cytochrome c. This is my first attempt running this ladder on w398, one of the new pinhole free membranes. From the TEM pics, it seems that w398 has pores all around the 50nm range, which is…
Chris and I got to play on the new Zeiss scanning transmission electron microscope (STEM) today (learn about STEM here). We didn’t get to spend a lot of time on it, but here are some quick images we snapped. wafer 416 @ 25kx (left) and 65kx (right) Even though we’re imaging in transmission mode, the…