Closed Flow System Update
Just an update on the PDMS-pncSi closed flow systems progress…
The issues we were having early last week with bonding seem to have been solved. We used to run extra ozone flow for ten minutes after the initial 5minutes of UV Ozone. As it turns out this is unnecessary, we are able to get nearly 100% bonding without it.
Last week Henry was able to get a sealed system and was able to get fluid flow through it. Under the scope he was able to visualize flow through using 15nm beads. Unfortunately before any pictures were able to be taken or a movies made the system began to leak due to the appilcation of a high amount of pressure.
On Friday I attempted to recreate Henry’s sealed system (n=4). To seal the entrance of the capillary tubing into the membrane chip PDMS system I used a small amount of uncured PDMS “glue” and allowed it to sit over the weekend at room temperature. Henry had tried a similar proceedure last week but he cured it in the oven and found that the heat caused the PDMS “glue” to become less viscous and flow into the trough of the membrane chip and clog the capillary tubes. He was able to over come this problem by using a small amount of vacuum grease and then applying the PDMS “glue” on top. When I made the systems on Friday we decided to try without vacuum grease and let it sit at room temperature. The result was identical to if the systems had been placed in the oven.
Today I will try again using vacuum grease, PDMS “glue” at room temperature and hopefully tomorrow we will have sealed systems and be able to get some picture and movies of beads flowing.