I am doing research on continuous metallic nanoparticle synthesis in a flow reactor. During the synthesis, fouling (scale deposition) is observed on the inner surface of the tubular reactor as the schematic view shows. It is a uniform deposition radially across the surface but it only occurs in specific section along the tubing. The composition of the deposited material is probably just pure metal such as gold and silver. I want to determine the rate of scale development, how fast materials deposit on the surface (thickness per unit area and time or mass per unit area and time). I am interested in analyzing the properties of the layer deposited, such as the thickness, composition, roughness, etc. I was wondering could quartz crystal microbalance, optical profilometry or ellipsometry be used to get time-resolve data? Can it be used for in situ characterization if I design some kind of flow cell? or is there any other technique that you think may be helpful in this case?
Dear Jiaqi,
It depends on the rates and thicknesses of the coating, you budget and desired precision.
Low-cost solutions are light absorbance fo thin coatings (1-100 nm range). Higher cost is a UV-vis spectrometer so you can infer particle dimensions and double-check the thickness via interference.
For thick coatings, you may measure pressure drop with a pressure transducer at a constant flow rate. You may try to measure conductivity of the layer.
Regards,
Nikolay
Thank you very much for the suggestions. I will look into the pressure and conductivity measurements.
I have UV-vis spectrometer in my lab. But I am not sure how it can be used to get the thickness of deposition via interference? Nikolay Cherkasov
UV-vis may have 2 uses, but you need to set the tube inside a holder so light goes through, but not around the tube.
When metal deposits on the tube, you absorbance will fall. You will not get the thickness values, but after some calibrations you may get good indications on the thickness. It only works for very thin coatins of 1nm-1um.
The color of the film will also change with thickness and you may use it for calibration of absorbance - https://en.wikipedia.org/wiki/Thin-film_interference
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