Tag Archives: nanotechnology

Creepy, crawly chemistry

Source: http://en.wikipedia.org/wiki/File:Nerr0328.jpgWhen lab work gets frustrating, I ask myself: can’t there be an easier way? I’ll hazard a guess that if you’re a chemist like me, you’re inured to the frustration of traditional synthesis. Often, it is the most well-behaved chemical reactions that get you at the end. Yes, I’m talking about that scale-up: that step you promised your adviser would be “facile,” as well as those extra TLCs you could, should, and wish you had done before you started your column. I’m of the opinion that many of the synthetic struggles in the early stages of grad school are essentially self-inflicted. It always cracks me up when I hear someone vigorously complaining about running a notoriously nasty reaction. Honestly, did you really think deciding tackling a McMurry or Skraup wouldn’t cause you just a little bit of sweat? I guess many young grad students, like me, have a burning desire to prove their stripes en route to their secret aspiration: becoming the most interesting man woman in chemistry.

I’m currently in the midst of working to overcome a synthetic hurdle of my own. Without getting into its provenance or name, I’ll say that I am quite determined to successfully duke it out with this particular reaction. Last week, while I was wrapping up in lab and was in the midst of drawing up the battle plans for the next day’s synthetic attack, I had a rather painful realization. Washing and prepping glassware can be a mind-numbing task and as I stood there essentially doing my dishes, I recalled a recent high impact paper detailing the biosynthesis of quantum dots in earthworms.

Nanoparticle distillery

Just in time for the holidays, research out of Naomi Halas‘s group at Rice University shows that nanoparticles can do what we’ve been waiting for all along: distill alcohol. The Halas group is known for making gold nanoshells, consisting of a 60-120nm silica core coated with 10-20nm of gold. The silica core is made colloidally by reacting silica monomers in the presence of a micellar surfactant. Then, the gold shell is applied by reducing gold ions on the surface of the silica.

These nanoparticles have interesting optical properties, including absorbances in the near infrared. The group has used these nanoshells primarily for cancer therapy due to their local heating properties. Luckily, that same surface heating effect can be used to efficiently create steam… and distill alcohol.

Super scopes (part 1)

In the latest issue of the Berkeley Science Review, we profiled the exciting development of graphene liquid cell technology at Lawrence Berkeley National Lab and UC Berkeley. This technique allows microscopists to visualize real-time nanocrystal growth in a transmission electron microscope. You may have caught us bragging a little bit in that article about the specific microscope Cal researchers used in that work. We usually try to be humble but when it comes to electron microscopes at Berkeley, that’s extremely hard to do.  In fact, our extraordinary microscopy was one of the reasons I was so excited to start graduate school here in the first place. In this multi-part post, I’ll be giving you a whirlwind tour of a few amazing microscope systems around campus. Hopefully, I’ll be able to convince you that these amazing instruments should be yet another reason to walk around campus with some serious Cal pride.

Whether or not you’re a scientist, chances are that if you’ve ever taken a biology class you’ve seen your fair share of transmission electron micrographs—the black and white photos with the arrows pointing at the different components, remember? Those images were showing you images of individual cells. Well, today that should seem huge because we’re taking a trip way down to the bottom, as Feynman would say. The electron microscope I’ll be talking about is capable of producing directly interpretable images of individual atomic columns with picometer spatial resolution.

Structural color

Researchers in Singapore are pushing the boundaries of printed color. In a recent issue of Nature Nanotechnology, Joel Wang and coworkers report a method of printing diffraction-limited pixels using the structural color of metallic nanostructures. Structural color refers to materials which derive their pigment from the interaction of tiny mico- or nanometer structures with light, rather than the absorption of light that occurs in most organic dyes. The light scattered by silver, for examples, can be different colors depending on the structure (size, shape, aspect ratio) of the metal at the nano-scale. In this recent paper, the idea of structural color is refined to create extremely high resolution printing. Specifically, arrays of nanometer-scale glass posts are coated with silver; the size and spacing of the posts controls the color of each pixel consisting of a 2×2 post subarray. The result is a remarkably reproduced Lena image, a standard test in the imaging community.