I want an even dispersion of aluminium oxide nanoparticle (30-60 nm) on the substrate but going through the primitive route (dispersion of nanoparticles in water or ethanol followed by ultrasonication) is difficult or almost impossible to get an even distribution.
I don't want to switch to another method. Kindly share some scientific idea and knowledge about which solvent would be the best for separating the nanoparticles as well as getting an even distribution on substrate.
Thanks in advance
Pranay Ranjan
If you're unhappy with your outcome and 'don't want to switch to another method' then you're in the same boat and the outcome is the same - unhappiness...
Dear all, the attached file resume the different methods followed to prepare Al nanoparticles. Hope it brings the necessary help. My Regards
I suggest the following paper
https://www.nature.com/articles/s41598-020-59710-z
It could be quite difficult to get the desired result if you want to keep using the same procedure. However, you may design a promising deposition process, at least for a class of substrates and range of np concentration in the original liquid dispersion, The dispersant plays a crucial role, not only in assuring enaugh stability of the dispersion before deposition, but also for its interaction with the surface to be coated.
As a matter of facts, the substrate mateerial and surface morphology play a role in terms of wettability with the liquid host at given thermodynamic conditions. For example, you may want to engineer the substrate surface in order to make it hydrophilic or hydrophobic if your np is dispersed in water. If you are going to try drop casting, an hydrophilic (or HYDROPHLIZED( substrate surface is preferred, that is very low contact angle with the dispersant. But also in this case, the result could be not that good, considering that the local nanoparticles conentration after drop deposition may be strongly inhomogeneous (as a matter of facts, at the edge of a casted drop the np concentration would reach so high values to form local aggreagates of the same nps on the surface).
A possibility is to deposit your np by fine- or ultrafine-spraying, with dropòlet size less than, say, 20um. A spayer may be easily built with the proper nozzles, rastering mechanism and pumping system.
I would concentrate on this latter route, using water dispersed nps (if such dispersion is stable enaugh) and droplets in the 10 um diameter range.
Hope having given you some ideas to go ahead.
Dear Pranay Ranjan;
Ethanol/water in an 80/20 volume ratio could be a more efficient suspension medium in terms of better colloidal stability, but also in terms of the quality of the microstructures of the deposits. In addition, to further increase the stability of the suspension, it is necessary to use acetic acid as an additive.
With my best regards
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