In the last month, we’ve run several sets of 15 nm pnc-Si wafers over a range of RTP temperatures. Below is a chart that illustrates the current pore size control we have by tuning annealing temp. The 900 C, 950 C, and 1000 C samples were from wafers SC 231, SC 314, and SC 316,…
Building on my recent posts I ran an experiment with SC267 testing the ability of BSA and DDM to diffuse through UV-Ozone treated (20min at 150C) and untreated samples. I used four samples testing both BSA and DDM in the treated and untreated cases using Jess’ diffusion cell. Again 6uL was placed on the membranes…
In order to further test the model, I’ve set up additional rhodamine diffusion assays. In each case, the setup is similar to the nanoparticle/protein/dna separations – 20 uL of .5 mM rhodamine on the top of a SepCon and 20 uL .1 M KCl on the bottom. Two different membrane geometries were used so far…
In my last post I presented the results of an experiment in which it appeared that BSA did not diffuse through a SC267 sample treated in the UV-Ozone system for 20min at 150C. As a control I also ran BSA dissusion through an untreated SC267 sample and showed that BSA did move across the membrane….
Frustration with the lack of agreement with experimental device has led me to check if the diffusion in the wells within the model is physically relavent. To do so I’ve solved a partial differential equation pertaining to a concentration of 1 on the left half of the system and a concentration of 0 on the…
As mentioned in my previous few posts Justin and I have been working to characterize contact angles resultant from various exposures in the UV-Ozone system. Earlier this week we got our new oxygen tank installed and it appears that after using the 15min cleaning protocol (15min@150C with vacuum) noticeable decreases in contact angles can be…
In effort to understand the model, I have been studying simple diffusion experiments using rhodamine, a small molecule expected to experience little hindrance. The model currently expects a small molecule the size of rhodamine to reach equilibrium within 1.5 hours. In the following figure, the retentate is blue while the filtrate is green. I…
Continuing the project that Mark had been working on, I have made some progress towards electroosmosis. Specifically, I was able to observe electrolysis through an intact membrane. Hopefully I will be able to observe electroosmosis through the movement of microspheres or nanoparticles through the capillary tubes. I tried a few variations of Mark’s design using…
This is an update of my progress with the diffusion model. Sieving coefficients for standard setup (Renkin only) In this image there’s a strong sigmoidal curve for the 24 hour diffusion. However, the cutoff (~34nm) is higher than cutoffs found in experiments. The lower time curves have unexpected shapes. This may be due to…
Last week I made a post showing the diffusion of DDM and BSA through SC267. I an effort to increase the negative charge associated with the membrane material I proposed using UV-Ozone exposure. A while back there was some concern that the UV-Ozone system was contaminated by PDMS, and that a standard cleaning protocol needed…