I would like to ask about the best conditions of sonication of graphite oxide in terms of apparatus (probe or bath), time and power in order to effectively exfoliate the graphite oxide without damaging the structure of GO sheets. The objective is to obtain water dispersion of about 5 mg/mL of the highest possible quality.
Thank you very much.
Hello Rodolfo Fernández-Martínez ,
You've asked a very useful, applicable question.
My understanding is that bath sonication is appropriate for a good dispersion of graphene oxide or GNPs (Graphene nanoplatelets).
Causes of ultrasonication time , power, and solvents :
1. Increasing the ultrasonic time or power helps GNPs spread out, but it can also increase the degree of fragmentation and improve the exfoliation effect. Fragmentation not only makes edges look like armchairs, which is a kind of defect, but it also makes the aspect ratio of GNPs smaller, even though the crystallinity of fragmented GNPs can be slightly improved. Also, sonicating for too long or with too much power can make the C-atoms spread out more randomly. So, the time or power should be cut down as much as possible to make sure the effect of dispersion happens.
2. Solvents with a low temperature, low viscosity, or high surface tension help GNPs spread out and break apart, but at the same time they make fragmentation worse. Due to the hydrophilicity of GNPs, it has a low degree of fragmentation in tap water, which has a high surface tension. It also has good dispersion and exfoliation effects. But it has some obvious flaws, like being hard to dry and possibly reacting with some active metals.
This article may be of importance to you:
1. Ultrasonic exfoliation of graphene in water: A key parameter study
Article Ultrasonic exfoliation of graphene in water: A key parameter study
2. Study of Ultrasonic Dispersion of Graphene Nanoplatelets :
Article Study of Ultrasonic Dispersion of Graphene Nanoplatelets
This article should be helpful and clear up any doubts. Wishing you success with your research Rodolfo Fernández-Martínez !
Best wishes and regards,
Vishwajit Chavda
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