There has been some experimentation recently on trying to form very large pores in thick membranes.  We have found that a high temperature anneal (1000 C) along with a fast ramp rate (100 C/s) w/o the susceptor can create these…

For the last three weeks, we have increased the substrate bias power from 25 W to 32 W (for both oxide and a-Si) to adress some film quality issues.  I have found that it is “harder” to open pores in…

I have been working on using the membranes to trap blood cells so that I can take force measurements with the AFM.  It is impossible to perform AFM on blood cells resting on a coverslip because the water displaced by…

Dave gave me some carbonized samples several weeks ago to test stability/discoloration.  I measured the contact angles right after I got the samples (posted here) and then started the discoloration.  These are SC141 chips.  Controls were untreated (1st column) and…

I have observed that in some cases the rate of EO can go up or down over the course of an experiment.  Often the initial burst in the first 5 minutes is high, then the rate may stabilize or drop. …

I got some new data on the pnc-Si capacitive sensor that has not been published on the blog yet. All of the results are summarized in the Spring MRS Proceedings paper mrsspring09_kavalenka. I also uploaded presentation that I made on…

This is a short review of a few experiments that Tom had set up this morning. Carbonized membranes: A few carbonized membranes that were used for permeability measurements were tested in EO.  The membranes were left in the sepcon, which…

Previously, I had data showing that 5nm gold in 10mM salts went diffused through pnc-Si membranes.  I was able to achieve this twice, although the second time took two days before the gold signal was intense enough to observe via…

Here are the results of diffusion based protein separations at different salt concentrations and 50kD Microcons: We see a sharp cutoff between 31 and 45kD.  Separations look like they have progressed further in 10mM salts rather than 100 mM (this…

Since the last post we have been working on obtaining replicates with wafer 101 chips.  The goal was to show salt dependent filtration changes.  These chips were different from the ones originally used in that the pores were much smaller…