Science in the Holy Land

Start with these, because I like to kill birds with stones.

• http://brandeis.facebook.com/album.php?aid=2002405&l=6ae39&id=1139280396
• http://brandeis.facebook.com/album.php?aid=2002437&l=ef4b7&id=1139280396

My mentor is named David Eisenberg. He's a pyromaniacal Ukranian living somewhere in Shomron who's doing grad work at Hebrew U. The goal is to find a way to get nanorods to attach to a polymer base in the desired fingerprint pattern to make some better lensing apparati.

We we 20 nanometer cadmium selenide rods with different ligands (polar and non-polar) and different solvents and strengths. They are supposed to align on either the PS or the PMMA part of PS-b-PMMA, 0r polystyrene-block-poly(methyl methacrylate), which looks like this: repeated a whole bunch of times. Each section (the PS is on the left, the PMMA on the right) is 20-25 nanometers wide. Depending on the polarity of the ligands attached to the nanorods, the rods will be attracted either to the hyrdophobic PS or the not-water-hating PMMA. So we have a whole list of variables: concentration, solvent nature, length of time drying, etc.

The solutions dilutions have obviously been the easiest part to master. There's some simple equipment that it would have been nice to have used back at school (such as the 100-1000 µl pipet adjusted with a thumbscrew) but it's not too hard to figure out. My specialty has been cutting the silicon wafer on which the PS-b-PMMA makes the top layer with a diamond knife. My two lab mates have had their turns floating the post-nanorod wafers into hydrofluoric acid and have both failed; I think my turn to fail is tomorrow. There are a lot of places that the procedure can fail and so far we've gotten caught in most of them. Having two or three perfect out of a day of 15 is good, and having only 3 or 4 wafers flip over at some point in the process is also good. One of the 12 we finished yesterday didn't separate from the wafer and sunk in the HF. Another flipped so many times; a third floated on its drop instead of the drop drying on the wafer. And these things are so small that it hurts the back. But it's a fairly good environment (especially after we stole speakers from the lab and played walla, Israel's less-specific version of pandora).

What I just described is the mentoring program. We're in the lab from about 2-6 every afternoon we're here. In the mornings we do the Belmonte program, which (I think) is geared specifically towards pre-college kids. We started with quite boring simple labs (dilute titrations, absorption calibrations) but they're working to make them more up to our level. We did one comparing hookah and cigarette smoke. The only thing to know is that the SO2 levels are higher in hookah smoke. Our explanation is that we used a quick-light charcoal that contained a lot of sulfur. My opinions weren't changed by the lab, but then again my opinions are what the lab was intended to demonstrate. Neither is clean. The only problem is that they have a hard time defining hookah as unclean when they compare it against cigarettes.