Author: Greg Madejski

Here’s a few sketchup animations I made for Dean’s device, based on his PPG presentation last week:      

Poor English Paper used as a starting point: Silicon Nitride Etch Rate paper This is a continuation of the work I’ve done, attempting to make freestanding MgF2 nanomembranes (theory and deposition) using a Silicon Nitride nanoporous substrate. I originally  wanted to use hot phosphoric acid to remove the Si3N4, but since we do not have that…

I am attempting to fabricate a free standing, porous, MgF2 nanomembrane for Raman spectroscopy applications (see my previous post for background). To that end, I’ve used the Lesker p75 evaporator in the basement to deposit ~100nm of MgF2 on one of our nanonitride Sepcon chips (Wafer 1055, 50 nm SiN, 2% porosity, 20-40 nm pores)….

Pint Silicon Supercapacitor   Tejas sent me an interesting article about Silicon-based supercapacitors. I have made a previous post on potential uses for our membranes as separators in EDLC (electrical double layer capacitors), and one of the problems I posited was that the electrolyte chemistry seemed particularly inimical to silicon (KOH, Na2SO4). The authors in…

Wet Etching of Optical Thin Films   As a result of Christian’s trip and Kevin’s discussions with me, I have been wondering if we could make nanoporous MgF2 membranes for Raman spectroscopy. Part of the appeal in using our Si-based nanomembranes is that the volume they occupy in the observation space is extremely minimal. Even…

Sealing Patch Clamp Chips Canadian Patch Clamp Chip   I have been thinking about Handy Geldbard’s group and what would enable them to study groups of synapses. Currently, I am in discussion with Jennetta Hammond and Pat Lu trying to understand some of their needs and wants. First, I considered their use of small microchannels…

AFM images report Protocol: pnc-Si TEM  grids were mounted on thin silicone inserts. Surface treatments were applied to the grids. Except for the CellTak treatment, the treatments were all diluted in Hank’s Balanced Salt Solution (HBSS) and incubated with grids  for 2 hours and then washed off with PBS. CellTak was diluted in 0.1 M…

I’ve been using a Makerbot 2 for the last week or so, trying to see if we can use the same PDMS contact lithography techniques that we are all familiar with. In short, yes, but there is plenty of work to be done to make it a robust process for microfluidics.   Makerbot Printer The…

Over the last week, I’ve run a discoloration assay similar to one run a while back (Barrett’s post here). It was demonstrated in a subsequent paper (Agrawal2010) that annealing the pnc-Si films prevents discoloration of the membrane, which he tied to the nanomembrane remaining intact. I was given a few chips from the recent TEOS lot,…

  I have been looking into PLA (Poly Lactic Acid) plastic for use in our microfluidics. PLA is a commonly used material in 3-d printers, so it would be great if we could print out our microchannels for cell-culture devices. To that end, I wanted to see if the PLA plastic would react with our…