Adhesion of an elastic particle to a plane surface: effects of the inertial force and the van der Waals force

Modeling and measurement of stiction or adhesion due to van der Waals force between microstructures and micro-gripper tools are important for contact-based manipulation and assembly of microstructures. Microfabricated structures commonly feature rough tapered curved surfaces due to undercutting and surface alterations inherent in the microfabrication processes. While several theoretical models exist for calculating adhesive forces between microstructures featuring spherical, cylindrical and flat surfaces, a model for estimating adhesive forces between microstructures featuring tapered curved surfaces is lacking in the literature. This paper presents experimentally measured values of adhesion or pull-off force between a rough tapered curved microstructure from a rough plane surface using a custom micro-cantilever beam as a force sensing mechanism. The paper also introduces an approach to estimate adhesive force between a tapered curved surface and a flat surface by considering the tapered curved surface as a frustum of a cone bound between two cylinders and using the van der Waals force model for cylinders. It is shown that the experimentally measured adhesive force values lie within the upper and lower values of the theoretically estimated van der Waals force values for the two cylinders that define the tapered curved surface geometry.

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First direct measurement of van der Waals force

AccessScience ◽

10.1036/1097-8542.br0718131 ◽

2015 ◽

Keyword(s):

Direct Measurement ◽

Van Der Waals ◽

Van Der Waals Force

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FLUCTUATION-INDUCED RADIATIVE HEAT TRANSFER AND VAN DER WAALS FORCE FOR SPHERICAL SHAPES

Proceeding of First Thermal and Fluids Engineering Summer Conference ◽

10.1615/tfesc1.fnd.012853 ◽

2016 ◽

Author(s):

Yi Zheng ◽

Alok Ghanekar

Keyword(s):

Heat Transfer ◽

Radiative Heat Transfer ◽

Radiative Heat ◽

Van Der Waals ◽

Van Der Waals Force

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First-Principles Study on Graphene/Mg2Si Interface of Selective Laser Melting Graphene/Aluminum Matrix Composites

Metals ◽

10.3390/met11060941 ◽

2021 ◽

Vol 11 (6) ◽

pp. 941

Author(s):

Zhanyong Zhao ◽

Shijie Chang ◽

Jie Wang ◽

Peikang Bai ◽

Wenbo Du ◽

...

Keyword(s):

Interfacial Energy ◽

First Principles ◽

Lattice Mismatch ◽

Van Der Waals ◽

Aluminum Matrix ◽

Van Der Waals Force ◽

Aluminum Matrix Composites ◽

Matrix Composites ◽

Charge Density Difference ◽

Interface Charge

The bonding strength of a Gr/Mg2Si interface was calculated by first principles. Graphene can form a stable, completely coherent interface with Mg2Si. When the (0001) Gr/(001) Mg2Si crystal plane is combined, the mismatch degree is 5.394%, which conforms to the two-dimensional lattice mismatch theory. At the interface between Gr/Mg2Si, chemical bonds were not formed, there was only a strong van der Waals force; the interfaces composed of three low index surfaces (001), (011) and (111) of Mg2Si and Gr (0001) have smaller interfacial adhesion work and larger interfacial energy, the interfacial energy of Gr/Mg2Si is much larger than that of α-Al/Al melt and Gr/Al interfacial (0.15 J/m2, 0.16 J/m2), and the interface distance of a stable interface is larger than the bond length of a chemical bond. The interface charge density difference diagram and density of states curve show that there is only strong van der Waals force in a Gr/Mg2Si interface. Therefore, when the Gr/AlSi10Mg composite is stressed and deformed, the Gr/Mg2Si interface in the composite is easy to separate and become the crack propagation source. The Gr/Mg2Si interface should be avoided in the preparation of Gr/AlSi10Mg composite.

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