Yesterday afternoon I made a new batch of 10:1 (base : curing agent) PDMS and put it in the oven at 80C for two hours to allow it to cure faster (compared to the three days it takes at room temperature). Once the PDMS was cured Henry used the UV Ozone system to again try…
W509X, with single 100um by 1000um slits, was tested for air permeability and burst pressure. Prior to testing, I inspected all membranes for pinholes.; every sample had pinholes on the membrane perimeter, as shown below. The first two images are in reflection mode (pinholes appear black) and the last is a transmission image (pinholes appear…
After posting my observed results from yesterday I came in today to find that one of the segment of the PDMS was strongly bound to the glass cover slip, so strong in fact that trying to remove it caused the cover slip to break. This result comes in response to the comment that Chris made…
Below are images from two samples that were annealed at 950 C and 1050 C post-EDP etch. The lower temp anneal produced a membrane with many features that do not seem to penetrate the nc-Si. There were a few (couple in each field) smaller pores ~ 10 nm in the outer samples. This supports Jess…
I talked with Jim last Friday about a second possible dialysis system using PDMS bound to a glass cover slip. I made a batch of PDMS and let it cure at room temperature over the past few days. Jim had suggested I try bonding the PDMS to a glass cover slip using the UV/Ozone system…
I tested four samples (-1,1); (-1,2); (-1,3); and (-2,4) for air permeability and burst pressure. The first three samples showed no measurable air permeability for three attempts each. The sample from position (-2,4) did have a very small air permeability of 11.2 cc/(cm2*atm). Based on the results of rhodamine diffusion it seems odd that I…
w565 is permeable to rhodamine. I tested two chips using 100uM rhodamine using a time step of .5 minutes. Click on pictures to see animations. position (1,-1) – While trying to do this first sample, MATLAB crashed and I was forced to take the movie about 7 minutes after the start. There is also a…
The only problem is the diffusion is very fast with defects in there.
One area of use to explore for the membranes is desalting, the removal of salts from solutions (such as those containing proteins). Two dialysis products made my Thermo/Pierce were tested to develop a protocol and test manufacturer’s claims. These products are the mini-dialysis unit on the left and the dialysis cassette on the right; both…
HUVEC adhesion was tested on different substrates. This time solid chips w/o membrane slits were used and expected results were obtained. I think from all the adhesion studies done, it could be concluded that initial adhesion on pncSi is as good as any other favorable substrate. Hence, the initial low density on pncSi was due…