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New insights into sono-exfoliation mechanisms of graphite: In situ high-speed imaging studies and acoustic measurements

Morton, Justin A.; Khavari, Mohammad; Qin, Ling; Maciejewska, Barbara M.; Tyurnina, Anastasia V.; Grobert, Nicole; Eskin, Dmitry G.; Mi, Jiawei; Porfyrakis, Kyriakos; Prentice, Paul; Tzanakis, Iakovos


Justin A. Morton

Mohammad Khavari

Ling Qin

Barbara M. Maciejewska

Anastasia V. Tyurnina

Nicole Grobert

Dmitry G. Eskin

Kyriakos Porfyrakis

Paul Prentice

Iakovos Tzanakis


The application of ultrasound and acoustic cavitation in liquid exfoliation of bulk layered materials is a widely used method. However, despite extensive research, the fundamental mechanisms remain far from being fully understood. A number of theories have been proposed to interpret the interactions between cavitation and bulk layered materials and hence to explain the mechanisms of ultrasound assisted exfoliation. Unfortunately, most of the research reported to date is ambiguous or inconclusive due to lack of direct real-time experimental evidence. In this paper, we report systematic work characterising cavitation emissions and observing the exfoliation of graphite in situ, in deionised water under the dynamic interaction with laser and ultrasound induced cavitation bubbles. Using ultra-high-speed optical imaging, we were able to determine the dynamic sequence of graphite exfoliation events on a time scale never reported before. Real-time observations also revealed that shock waves with a pressure magnitude up to 5 MPa and liquid-jets in the range of 80 ms−1, from transient cavitation bubble implosions, were essential for the initiation and propagation of the exfoliation process. On the other hand, bubble oscillations associated with stable cavitation were beneficial for promoting a gentler delamination of graphite layers.


Morton, J. A., Khavari, M., Qin, L., Maciejewska, B. M., Tyurnina, A. V., Grobert, N., …Tzanakis, I. (2021). New insights into sono-exfoliation mechanisms of graphite: In situ high-speed imaging studies and acoustic measurements. Materials Today, 49, 10-22.

Journal Article Type Article
Acceptance Date May 5, 2021
Online Publication Date Jun 24, 2021
Publication Date 2021-10
Deposit Date Apr 1, 2022
Publicly Available Date Apr 5, 2022
Journal Materials Today
Print ISSN 1369-7021
Electronic ISSN 1873-4103
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 49
Pages 10-22
Keywords Ultrasonic exfoliation; Sono-exfoliation; Cavitation; Shock wave; Liquid-jet; Acoustic streaming; Graphene; Bubble dynamics
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