Hello, I have been working on the synthesis of carbon dots (CDs) by electrochemical method, and I have been using monoethylene glycol as a surfactant agent, to avoid agglomeration of the CDs, however, agglomeration still occurs in the resulting solution, for this reason, I would like to know If anyone has any experience with any other type of surfactant or if someone could please guide me on what I may be missing to avoid agglomeration in the CDs.
In advance, many thanks to those who take the time to share their knowledge.
Tomas Rodríguez You need a stabilizer not a surfactant. You have aggregation (tight) not agglomeration (loose) in your system. Take a look at this webinar (registration required):
Dispersion and nanotechnology
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W190528DispNanoMat
Tomas Rodríguez
You need to spread the paste (aggregated quantum dots) evenly across the CD. Therefore, you did not use surfactants, but ethanolamine. This component can be called not a suspension stabilizer, but a paste plasticizer. We used sulfonic acids for these purposes: toluenesulfonic acid, polystyrenesulfonic acid. It is necessary to choose the optimal concentration.
Thanks to prof. Rawle and prof. Migorod for thier answers to this question.
Dear Tomas
There are so many reports on the synthesis of CDs. in the literature, via either top-down or bottom-up approaches for different purposes. I wonder why you don't use a proper method from the vast reported approaches.
Dear Mohammad ,, you can use ultra sonic apparatus such as spin coater to avoid agglomeration after synthesis .
Hi dear Tomas,
Dr. Rawle and Prof. Mirgorod fully addressed the raised issue. You need to use a stabilizer to prevent any aggregation. A wide range stabilizers have been proposed to mitigate or even stop the aggregation process and amongst them alkali salts like NaOH and KOH are conventional ones.
Also, I investigated one of the possible aggregation mechanisms of CQDs in my recent paper which may help you to understand aggregation behavior of CQDs.
Article Cation-π Aggregation-induced White Emission of Moisture-Resi...
Kindly let me know if you are willing to read the full-text. I would be happy if it helps you in your career.
Best wishes,
Arman
to add glycols are no surfactants, unfortunately, using the definition - surfactant = surface active compound - almost all chemical substances would be a surfactant.
CQD or other nano material have strong agglomeration tendency and will be avoid by dispersing nano- material in aprotic solvent like DMF and sonicated properly. It will diminish attraction between them and disperse uniformly. Some time we can also used diluted stabilizer as depends on desired property.
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