Mathematical Models for the van der Waals Force and Capillary Force between a Rough Particle and Surface

The current paper deals with the problem of static instability of Micro/Nano mirrors under the combined effect of capillary force and van der Waals force. First the governing equations of the statical behavior of Micro/Nano mirrors under the combined effect of capillary force and casimir force is obtained using the newtons first law of motion. The dependence of the critical tilting angle on the physical and geometrical parameters of the nano/micromirror and its supporting torsional beams is investigated. It is found that existence of vdW torque can considerably reduce the stability limits of the nano/micromirror. It is also found that rotation angle of the mirror due to capillary force highly depends on the vdW toque applied to the mirror. Finally analytical tool Homotopy Perturbation Mehtod (HPM) is utilized for prediction of the nano/micromirror behaviour under combined capillary and vdW force. It is observed that a sixth order perturbation approximation accurately predicts the rotation angle and stability limits of the mirror. Results of this paper can be used for successful fabrication of nano/micromirrors using wet etching process where capillary force plays a major role in the system.

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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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