Work today was good.
First off, things are working. I'm currently doing an electrochemical etch of a big thing covered in graphite, and I'm using weighing and pictures to attempt to determine the rate of the etch. So far, it has been pretty successful. Once I get more data points, I'll figure out some way to make the data useful so that it can be compared to further tests, with some variables. My boss suggested normalizing the data by getting percents of weight lost, which is probably what I'll end up doing. This is the first time I've really gotten to work interestingly with data, and to try to figure out on my own what to do with it and how to interpret it. In all the labs in high school, they make you take data and then tell you exactly what to do with it, and you've probably already learned what it means anyways. In this case, I don't really know what it means or how it relates to the variables. Very exciting. I think it would make a great science fair project, if that was what I was going to use it for.
Next interesting event was that I spent a bunch of time talking with my boss about the mechanism for the etch. This is something that no one knows, and that has mystified us from the beginning. If we knew the mechanism, we would know better how to improve the rate of the etch! Our current theories are as follows:
1: Some sort of reactive element or ion (OH-? H+?) is being created in the water and reacts with the graphite in some way, possibly to create CO or carbon dioxide. The problem with this is that most of the etched graphite seems to end up floating as macro-sized particles in the water, indicating that they've fallen off for some reason, which seems against the reaction to form gas unless this reaction likes to occur in crevasses underneath the graphite, taking away a layer and knocking everything above it off.
2: The conductive graphite in the water creates a short that leads to a potential buildup on either end of the graphite, which causes the breakdown of water and possibly some sort of reaction to occur? This on is fuzzy, but it makes sense that this sort of potential buildup would occur.
3: This idea is weird, and seemed to be suggested in one of the papers I read. They seemed to think that the passage of current through the graphite may through random interactions (kind of like london dispersion, I guess) cause carbon atoms to momentarily become polar enough to be dissolved into the water. Again, if this were to happen, no visible graphite would be floating around in the water, unless it either ate below them or the graphite, after dissolving off the main structure, would fall out of solution and create visible particles.
With each of these potential mechanisms come potential ways to increase the rate:
1: Figure out how to create more of this ion, possibly with more current. Also, try to allow more of this to reach the surface of the graphite and avoid buildup of a layer around the graphite, either through ultrasonic agitation of the water or mixing.
2: Use the purest least conductive water possible to make the potential difference across the graphite greater. Again possibly agitate the water to prevent the buildup of a layer.
3: More current. Possibly adding a surfactant (which the paper says they did, and that is slightly improved some of their performance)
Apart from this, my boss now wants me to find information about Diamond-like hydrocarbons, and the atomic hydrogen density of various types. So far, I've had little success in this, but I've not spent enough time.
As always, more to do!
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