NPN membrane: Streaming potential measurements
Update: After doing several measurements again, it appears that the data shown below were not repeatable. It is believed that these data were just the artifact. Please see my new blog post “Flow Sensing and Energy Harvesting Capabilities of NPN Membrane” for a new data set.
Here are the streaming potential measurement data for NPN membrane in 100 mM NaCl(aq) solution. I did the measurement about half an hour after assembling the membrane into the test device. Normally, I waited for at least 18 hours before I measured the open-circuit potentials for the pnc-Si membranes. I will do the mesurements again in the evening.
What I observed was the open-circuit potentials did not change instantaneously after the flow rate was changed. It took about 10-20 minutes. I expect that after the membrane has been in the solution for 18 hours (surfaced charges fully developed), there will be an improvement in the response time. I will update this post.