Some of you may remember me from last year - that new PhD student who studies the sol-gel process with Anomalous Small Angle X-ray Scattering. Then, of course, I was developing a method of producing clear, homogenous YSZ that would gel over the course of a few hours. The experiment was a huge success - particularly in the sintering of YSZ gels to ceramics. And in a few weeks we are taking this one step further with an in situ grazing incidence experiment on coated substrates.
My next mission is to grow zinc nanoparticles in a silica matrix, and orientate them in an electric field. Initial attempts have been puzzling to say the least. Literature suggested dissolving Zinc Acetate in Methoxythanol and Ethanolamine to produce the zinc sol. This is widely used in dip coatings to produce 2-0-0 orientated ZnO crystals.
I thought, at least, that by mixing this sol with a straight TEOS-alcohol-0.1M nitric sol-gel would give me the desired product. However - it seems I was wrong! The zinc did not crystalise as I hoped it would. What occured instead was either a clear gel, or a white precipitate (more than likely a silicon compound) with "larger" quantities of Ethanolamine.
What is more, XRD revealed no crystals, even on sintering, which surprised me. I also discovered quite early on that Zinc Acetate was not as soluble in MEA as I had originally been led to believe. It dissolves a treat in Citric acid solution though - however, Zinc Acetate and Citric acid produced a rapid precipitation with alcohol - not so good for trying to grow the crystals in a silica matrix.
Now... The matrix does not have to be silica - in fact, I've considered using Alumina instead (though the alkoxide precursor materials appear to be far more reactive than TEOS) I just want to grow zinc nano-crystals in a sol and orientate them in a field during an in-situ experiment.
Do you have any ideas or suggestions as to what I could try? I have all of summer to try out various methods and precursors before the beamtime at Diamond Light Source in September.