The permeability data is very different for films deposited at room temeperature and 400C.The 400C deposited wafers have much higher permeability and more consistent. w335 – RT w336-RT w338 -400C w340 – 400C Burst Pressures

The ‘Tong equation’ for liquid flow through a nanosieve is I refer you to the original paper for variable definitions (see page 285). For the flows that we see, this will always simplify to the much simpler equation … We can first appreciate that the factor will be ~1. This term decreases with increasing porosity…

We have recently been discussing the best way to analyze the diffusion and SepCon separation gels. In the following figures, I present line scans of the gels. These appear to be a bit noisy and are somewhat misaligned due to variations along the length of the gel. Blue = Control, Green = Retentate, Red =…

Using wafer 302 I set up 2 20nm and 2 50nm gold diffusion experiments. After 24 hrs I removed the retentate and filtrate and looked for the gold using the Malvern Zetasizer. We can’t perform the diffusion with both 20nm and 50nm gold because the Zetasizer cannot differentiate between the two sizes. r value Sample…

Last week we processed wafers 335 – 340. Our goal was to track down the source of Cu contamination. We sputtered membrane films both at room temperature and at 400 C. Our thought was that the RT dep. would not show contamination if the sputter heater was indeed the source of our Cu. It turns…

There is some non-uniformity in air permeability based on the position but it is not very clear for wafers 318 and 319. The full wafer measurement in future will make this dependence more obvious.Permeability of w319 is much higher then of w318 (RTP 1000C and 900C) as expected from TEM images where w319 has higher…

The 300K nanosep membranes that Jess ordered came in so I ran a single set of three membranes at 21.63psi to compare their hydraulic permeability values to those of the 100K microcon membranes. As expected the 300K nanosep membranes have a much larger hydraulic permeability then that of the 100K microcons; approximately a factor of…

Having finished the hydraulic permeability testing with DI water I wanted to see what the effect of an introduction of protein would have on the permeability values. To do this I simply reran a set of fresh membranes at 21.63psi using a 1mg/mL solution of bovine albumin in PBS instead of water.The group on the…

When I first starting testing the microcon filters I noticed that if they were allowed to sit overnight (exposed to air) after having been already tested with water the next day if they were tested again the permeability of the membrane decreased significantly. The membranes come pre-wet with trace amounts of glycerin; spinning with water…

Last week, I took some of Jess’ 20 nm Au colloids and placed them on a membrane for imaging under TEM. I took images at each of our standard magnifications. Using Mike B.’s pore counting program, I generated statistics and calculated the pixel-to-nm conversion ratio assuming the gold colloids were 20 nm (< 10% variation)....