Condensed Matter National Laboratory




Bending stiffness of 2D membranes

Collaborators

(Internal): Seyed Mohammad Reza Taheri
(External): Ali Sanjari (Jetco Co.)
(International):
Mohsen Moazzami Gudarzi (University of Manchester), Alexandara Satalov (Leibniz University)




Funded by

Swiss National Science Foundation (P400P2_186747 & 174952), Iran Science Elites Federation (11/66332) and international affairs and technological exchange centre of vice presidency for science and technology (99/200/4419)



Published Papers

1- Anomalously low electrostatic bending stiffness of graphene oxide 2D membranes regulates their environmental fate in aquatic ecosystems, Journal of Materials Chemistry A, 2022

2- Superflexibility of Graphene Oxide, PNAS, 2016, 113 (40), 11088-11093


Summary in English and Photo


The mechanics and conformational stability of atomically thin membranes in dispersions, have been controversial issues subject to debate. This, mainly stems from the fact that there are many inconsistent, often contradictory, reports on the measurement of the bending stiffness of these intriguing materials. While the tensile properties of 2D materials is straightforward to measure, when it comes to measuring the bending stiffness even for the simplest form of 2D materials, i.e., graphene, there is a broad range of values reported, spanning over four orders of magnitude. Given the fact that it is the stiffness of these materials that governs their conformational behaviour in aquatic environments, which in turn, affects the transport and fate of these systems in water pathways, the general lack of knowledge regarding the origin of the rigidity in 2D materials poses a great threat that needs to be addressed if the full potential of these intriguing materials is to be realized. Here we show that contradictory to common belief, the electrostatic contribution plays merely a minor role on the rigidity of graphene oxide (GO), the most studied member of the ever-increasing family of 2D materials. We present evidence that the flat geometry of GO is very persistent in aquatic environments even after the addition of metal ions of different valences positing that 2D membranes pose a more significant threat to the environment than what was envisioned before. This also leads to the revisiting of the century-old Schultz-Hardy rule for the coagulation of low dimensional colloids, resolving the misconception regarding the transformation of 2D membranes into 3D particles.


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