Gold nanowires

So this week I met someone on the bus.  I have met her before and this time we started chatting. She is a chemistry teacher in a high school.


I liked the idea of learning chemistry when I went to secondary school. It sounded exciting, mixing and burning things.


I was however completely put off by my chemistry teacher. "Dr Pockets", he wore a tweed jacket and the black gown. He wasn't very good but worst of all would come up behind you and poke you in sides with two fingers. I didn't like that or him so I completely switched off from chemistry and dropped it as soon as I could. Perhaps that is why I became an engineer.



Anyway my new friend the chemistry teacher was telling me about what she did her PHD in. 


I may get some of the terms wrong but she was researching making mirrors by dissolving silver in a solution. This would form a thin atom thick layer of silver that she would bounce lasers off. (How cool!)


She described how her lab would be dark as she setup a beam that was split and would go on different paths. One beam would take a longer path than the other to reach a detector and the difference in time would be measured along with their intensity. It would give interesting facts about the mirror, some of the light would be lost or absorbed.


The standard practice was to use silver and she pondered what would happen if you were to use gold? So she mixed up a solution of gold to find out. Under an electron microscope the gold behaved differently. No longer an atom thick layer or sheet of silver, the gold had formed into atom chains. Like tiny little snakes or wires. Bizarre! She didn't do anything with these wires and just put them down as a cool anomaly.


Moving on a few years, what she had created were gold nanowires. I've googled it and it's a real thing. Gold conducts electricity and the nano wires made from it can also conduct electricity.

At the moment they are being used in medical procedures. They are grown much like a snowflake, in an additive process building out from an electrode spike.


To give them some scale and put them into perspective they are 1,000 times smaller than a human hair. Thats tiny. Smaller than human cells.


In my googling I also came across the cost and if I were to buy some gold nanowires. I wasn't expecting them to be cheap but a handful (literal) of wires 30nm wide by 6000nm long delivered in a 10ml tub is £384.50. (June 2017)


I guess the bulk of the cost is in the manufacture rather than the raw material. They make gold more expensive than gold!


I have been pondering where else gold nano wires could be used, more googling found them used in flexible solar panels and batteries. Being so thin lots of them can give a larger surface area.


I still can't fathom the scale and how you manipulate things so small.


I always remember a story my dad told me. I think it was pre war, and the Germans in a show of engineering skill took a sewing needle and drilled a hole down its center and sent it to the British. The British, not to be out done took a cast of the hole in the needle and drilled a hole down its center and sent it back to the Germans. Many facts here may also be wrong but it was a good story about something tiny, and as a kid I could imagine the tiny drills doing the job.


So that's my new friend the chemistry teacher. Have to say much better than 'Dr Pockets' and I actually learnt something interesting.


Thanks for reading, and remember gold nanowires, you heard it first here.