I would like to share a collection of high resolution SEM images of nanopores of polycarbonate track-etch (PCTE) membrane. These nanopores have very high pore length-to-diameter aspect ratio of 6000 nm / 25 nm. I hope you find them useful. Cross-section of PCTE membrane Cross-sectional view of long and straight nanopores with a close-up at…
It is expecting that the high electric field gradient at the nanopore entrance could amplify the dielectrophoretic force so that the nanoparticles transported toward the membrane could be manipulated based on their polarizabilities. To prove the concept, the electric field was applied across the nanoporous membrane while a bolus of gold nanoparticles was delivered across…
Porous metal-organic framework (MOF) crystal is obtained by precipitation after mixing an aqueous solution of cadmium nitrate and the solution of 4,4’-bipyridine in anhydrous ethanol. It is found that the crystallization occurred when ethanol evaporated from the mixture. As a result, 4,4-bipyridine became supersaturated and complexed with Cd forming an infinite two-dimensional sheet as shown…
Please see the attachment: Crystal Growth inside Nanopores
Presentation in this post is based on the paper entitled “Large Area Synthesis of a Nanoporous Two-Dimensional Polymer at the Air/Water Interface”. Paper: Murray(King)JACS15 Supporting Information: Murray(King)JACS15 – SI Presentation Slides (PDF): Two-Dimensional Porous Membranes
Principle of Operation The electrokinetic properties of charged membrane make it possible for conversion between the electrical and mechanical regimes. The electroosmosis is an example of converting from the electrical to mechanical powers. In reverse, exchanging the mechanical energy for electrical energy relies on two electrokinetic phenomena – the streaming potential and current. Consider an…
It was expected that heating up the substrate during Au sputtering would help increase mobility of Au into nanopores so that the uniform coating on pore wall could be achieved. The result was quite unexpected; Au did not coat uniformly on pore wall nor the surface of membrane. Instead, Au clumped into nuggets of various nanometer-scale sizes all…
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…
A change in open-circuit potential, measured across a pnc-Si membrane, in response to a fluctuation in flow rate of electrolyte solution exhibits a promising flow-sensing capability of the membrane. To demonstrate this correlation, the open-circuit potentials were measured under a variety of pressured-driven flow patterns. In Figure 1, a series of flows under various applied…