We’ve heard it before, so you might as well say it with me (but not in public unless you don’t mind being seen talking at your device/s): money doesn’t grow on trees. Can’t be too free with money, and scientists know this all too well. ALL. TOO. WELL. But that’s another discussion for another time, preferably with a scientist who’s been through the process; today’s research article is about a renewable source of circuit-building material. ‘Renewable’ is a good thing, especially if you’re thinking in terms of dollars and cents (and yen and won and Euro and pound and peso) because in the long run, non-renewable materials such as rare metals will really start eating at your bottom line (oh stop snickering). That’s just materials – production can get rather pricey, which will keep competition down since some firms can’t afford to jump into the biz.
I am going to stop talking about economics now. Enjoy this while I get my head screwed on straight again:
Anyway, Seo et al. proposed a method of creating graphene films using soybean oil. I’ve talked about graphene before (there’s even a link to help explain what the stuff is, but here it is anyway), and its production involves a source of carbon first of all, and that’s where the soybean oil comes in. Also important is the process – a common method of creating thin films, which includes graphene circuitry, involves chemical vapor deposition. The short of it (with video!) is that using high temperatures and chemical reactions in a vacuum, your desired material (graphene in this case) is deposited and essentially baked on a thin surface. I went to university with someone whose research was mostly (if not totally) on this stuff.
So if this process is just so keen and nifty, why is there research to make a better process? While I’d like to say ‘because Seo et al. are scientists and that’s just how we live,’ (hit chest twice, flash peace sign) there’s more to it than that. It requires high temperatures, which costs money, and the chemicals involved are not only expensive (in terms of production and keeping it pure) but could also be hazardous. Hydrogen gas is a good example. Put all together and you get a rather difficult, if lengthy, production process to make graphene circuitry, which isn’t very large to begin with. This is why they opt for as few steps as possible (‘single’ – that’s about as few as one can get) at more manageable temperatures. They describe the process as getting up to 800°C, but not for too long – maybe about an hour. It also requires a catalyst (something to get the reaction started/moving faster but you get it back when you’re done so less used-up stuff), to which they use nickel foil. In the heating process, the carbon that makes up the soybean oil (all oils are mostly carbon anyway) split into smaller and smaller bits of carbon until they’re just individual atoms at 800°C, then they’re baked on the film. I’m not entirely familiar on how efficient chemical vapor deposition is and how long it takes with the usual method, but considering they’re using soybean oil and not-too-high temperatures, we’ll have to take their word that this is some kind of improvement until someone comes along with a more efficient method. 2017 is still early, after all.
Like with any materials testing, we ask the question: how well does the process work? Considering that they end up with graphene made of a single layer of carbon atoms, I’d say they have a hit since graphene is only a single layer of carbon atoms (any more than that and that’s graphite, which is pencil lead). So as far as an alternate method of creating graphene films, this one can work. Now, according to the title of this article, this is supposed to be used as a kind of biosensor, so this particular graphene film that they made must be up to the task of being cost-effective (check) and low-power while also doing what it’s supposed to do. They found that their film was able to pick out certain RNA sequences, even in the presence of biological gunk like uric acid and albumin, which sounds like the worst omelette.
So there you have it – the authors have found a way to produce sensitive, micro-scale electronics using techniques that are not only easier on the wallet, but gentler on Mother Nature. Since there’s a lot of R&D on more effective and probably less-explodey power sources as well as other methods of charging mobile devices (this one’s #1), we can maybe get to a point where producing mobile devices – likely a huge chunk of the consumer market, let’s face it – won’t produce too much of a dent on the environment. It’s something to aspire to.
Think of the kittens.
Featured Article: Seo DH, Pineda S, Fang J, Gozukara Y, Yick S, Bendavid A, Kwai S, Lam H, Murdock AT, Murphy AB, Han ZJ, Ostrikov K (2017). Single-step ambient-air synthesis of graphene from renewable precursors as electrochemical genosensor. Nature Communications 8: 14217. DOI: 10.1038/ncomms14217
Featured Image: Public Domain (Author: Julio César García)