Here is a slightly enhanced version of Mike’s latest hydraulic permeability data for commercial devices with PES membranes. The data at 22 and/or 34 PSI are a bit strange. Still the long-term trend seems downward. Similar data for PNC-Si membranes should show no pressure dependence. We need to get a version of this figure that…
Just some quick thoughts about the attached excel on my previous post… The 100K nanosep does not have a hydraulic permeability value at 194.65psi because it passed all 500uL of water through in 1minute which is the smallest interval of time a test can be run at with the new centrifuge. When I get a…
I ran some more tests on the microcon and nanosep filtration systems at 21.36psi (4000RPM) and 194.65psi (12,000RPM). Both are rated for forces up to 14,000 time gravity which is about 340psi but after talking to Tom we thought it best to run it at a slightly lower pressure to account for any possible error…
Below is an optical image that shows the amount of area loss caused by the preferential EDP etch. Based on these numbers, our most recent membrane slits measure 115 um x 2014 um.
I found a small mistake in my calculations of the air permeability.Corrected data is in the graph below.
Today I looked at 3 more wafers: w158 (9/7/07) – some pinholes, overwhelming amount of very fine debris, not cbs as far as I can tellw160 (9/7/07) – some pinholes, debris, no cbsw171 (9/26/07) – many pinholes, lots of debris, no cbs w158 (200x) – small particles Link to updated report.
Two simple diffusion separations were performed before break using membranes from wafers 205 and 213 (locations unknown as these were salvaged/misplaced chips). I ran the samples I collected on a 10% SDS-PAGE gel today. It seems that the membranes were able to separate the standards at two different cutoffs. The missing band in the middle…
There is strong evidence that the recent pinhole breakout is due to copper contamination in our process. I have attached two image – An SEM showing a cuprous creature eating one of our membranes and an EDX (Energy Dispersive X-ray?) spectra identifying it as a copper-rich silicide. This would also explain Dave’s TEM image of…
Just in case you missed this one: www.nature.com.ezp.lib.rochester.edu/nnano/journal/v2/n11/full/nnano.2007.354.html This article makes the the previous papers seem mundane. It has inspired me though – maybe we can create a computer simulation that will demonstrate that pnc-Si membranes will dance and sing songs under the correct conditions. I will leave the choice of genre to the programmer…
I stripped and viewed samples from wafers 186, 185, 184 and 182. None of these samples had cigarette burns. Follow this link to the updated summary: cb_report Previously I had noticed cigarette burns (small ragged pinholes) on samples from wafers between numbers 202 and 216. All of these wafers had been stripped using a full…