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Published on: July 24, 2015
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Transparency of Graphene to Solid-Solid van der Waals Interactions.
Chuanli Yu1, Weijia Zeng1, Zepu Kou2
1Peking University, School of Mechanics and Engineering Science, State Key Laboratory for Turbulence and Complex Systems, Beijing 100871, China.
Physical Review Letters
|October 25, 2025
Summary
Two-dimensional (2D) materials like graphene can screen van der Waals (vdW) forces, impacting their use in nano-devices. This study quantifies graphene
Area of Science:
- Materials Science
- Surface Science
- Nanotechnology
Background:
- Intermolecular interactions, specifically van der Waals (vdW) forces, are critical for designing 2D material-based nanofluidic and microelectromechanical systems.
- Previous experimental studies on the vdW transparency of 2D materials have yielded inconsistent and contradictory results.
- A precise understanding of vdW force transmission through 2D materials is essential for advancing nanotechnology applications.
Purpose of the Study:
- To experimentally quantify the van der Waals (vdW) transparency of graphene, a key two-dimensional (2D) material.
- To investigate the influence of graphene layers on the vdW interaction between a probe and a substrate.
- To reconcile experimental findings with theoretical models like Lifshitz theory.
Main Methods:
- Utilized colloidal atomic force microscopy (AFM) with a geometrically well-defined probe.
- Measured pull-off and pull-in forces in a model system of graphene on silicon dioxide (SiO_{2}).
- Employed Lifshitz theory calculations for comparison with experimental data.
Main Results:
- Observed that the total vdW force deviates significantly from the sum of individual contributions of graphene and the substrate.
- Found that the effective surface energy of suspended graphene can be higher than substrate-supported graphene.
- Demonstrated that 1-5 layers of graphene screen 15%-50% of the intrinsic solid-solid vdW interaction.
Conclusions:
- Graphene exhibits significant screening of van der Waals (vdW) forces, contrary to simple additive models.
- The vdW interaction is modulated by the presence and thickness of graphene layers.
- Experimental results align with Lifshitz theory, providing a quantitative basis for 2D material vdW transparency.
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