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In an effort to better understand and check Karl’s model of sieving, I’ve built a significantly simpler version. The goal is to investigate the potential benefits of thinner membranes in dead-end filtration and separations. In my model 1 ml of water is displaced from the top bucket to an originally empty bottom bucket with a…

The new smaller EQ setup that Tom came up with were tested in these experiments. The benefit is that there is much less dilution of our filtrates. 500ul of our sample (in these cases we tested 1.0 mg/mL and 0.5 mg/mL brain extract) is loaded into the SepCon and 250uL of buffer fills the reservoir…

For the charge model, we would like to know the surface charge density and size of our experimental molecules.  I’ve attempted to use the Zetasizer for both measurements, but as mentioned in my diffusion paper, DLS gives sizes that deviate from the expected or crystal sizes.  Since zeta potential measurements require large amounts of highly…

  Overview I burst pressure tested TEM chips with 1×1 mm windows of 100 nm SiO2 that were both annealed and unannealed (provided by JP and Josh Miller). In our experience it seems that the forming gas (H2/N2) annealed chips are stronger and never wrinkle. These burst pressure tests were performed in an attempt to…

In the next paper that I’d like to publish, I will compare protein separations for two membranes with different pore distributions to a single membrane at two salt concentrations (basically a redo of this post).  My most recent trial with this had less than stellar results. I chose two wafers for movable cutoffs – SC…

Wafer 416-T is a TEOS wafer annealed at 900 C. Pinhole density is relatively low. left: (1,0) @ 35kx; right (0,4) @ 35kx left: (1,0) @ 50kx; right (0,4) @ 50kx