I recently performed an experimental separation with 4 proteins in 100 and 10 mM KCl.  All proteins are negatively charged at the pH of the experiments, and we would expect that less would pass through the membrane in the 10…

With some of the recent high porosity membranes being produced, I wanted to demonstrate that we can use ALD to create a movable cut-off without sacrificing too much in permeability. I took sc713 and coated it with 5 nm and…

I’ve been working with the AFM recently and have had some success getting images on supported pnc-Si films. Yesterday, I imaged three samples from sc 698: one untreated pnc-Si film and two films coated with aluminum oxide (1.5 nm and…

Today, I ran a quick experiment to confirm that water transport was not negatively affected by an aluminum oxide coating. I deposited 1.5 nm of Al2O3 onto a pnc-Si membrane which I then treated with an oxygen plasma in the…

Today while I was imaging a Al2O3 coated pnc-Si membrane on the high-res TEM, I noticed something curious as I placed the beam on a single pore for a few minutes. I was initially interested in the structure of the…

1) FIB. I tried to get a cross section of the pnc-Si with FIB with Brian’s help. The results are negative. It looks like the ion beam almost “melts” the membrane and destroys the pores instead of cutting.  The tool…

This is a quick post on comparing the contact angle after ALD on pnc-Si with aluminum oxide vs the untreated material (+/- ozone). The hypothesis is that the angle should drop since Al2O3 is hygroscopic. The angles are 85°, 45°,…

This is a follow-up to my initial report on using the ALD to coat pnc-Si pores with Al2O3. Below are the TEM micrographs and histogram of a series of depositions I performed with 3 different process times. I was targeting…

Today I made my first attempt at depositing aluminum oxide on pnc-Si using URInc’s Cambridge Nanotech’s Savannah 200 atomic layer deposition tool. Ritala and Leskela give a nice primer on ALD theory. ALD relies on layer-by-layer growth of film by…

Charles developed a new microEO chamber, and I did some quick particle tracking experiments.  The fluid in front of the membrane was filled with 200nm fluorescent polymer beads, and the power supply was used to cause the fluid to flow…