Hello,
I typically use sharp AFM probes to do friction measurements on silica. I blunt the tips somewhat and convert the apex to thick silica by annealing in air at very high temps, which produces a very smooth apex. Unfortunately, in recent experiments, the wear rate rapidly converts the tip to a punch which creates all sorts of problems for me.
I was hoping to work around this problem by moving to sililca colloidal probes, which are very common of course. My question is what is/are good supplier(s) to obtain colloids in an appropriate size range (10-50um I guess) for gluing to AFM cantilevers, and critically, with very low roughness values (
You say 10-50um so I assume you do mean microns. If so, suppliers of colloidal particles aren't necessarily your best option.
Instead, look for suppliers of silica size standards used for applications such as laser diffraction. e.g.,
https://www.chromspheres.com/product/nonporous-silica/
I'm not suggesting them, just using them as an example. The problem is that size standards tend to be expensive. Perhaps you could ask for a sample.
Alternatively, if you know anyone with a laser diffraction instrument (e.g., Malvern Mastersizer), they might have some standards. All you need is a tiny amount.
Thank you. This is the sort of thing I am looking for. The specific size doesn't matter so much for what we do, more that the geometry in the contact region is well-defined, which means extremely low roughness, and ideally a very pure SiO2 so the chemistry doesn't complicate things.
I'll try searching as you describe in addition to checking out this specific company.
Does anyone happen to have a good option with a known roughness? I found these https://www.microparticles-shop.de/Monodisperse-Particles-for-Research-Purposes/Silica-particles-SiO2-R-in-the-size-range-150-nm-25-m:::1_6.html which have a known roughness of
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