Capillary Condensation Adhesion Phenomena and Analysis of the Micromechanical Gyroscope

2013 ◽  
Vol 562-565 ◽  
pp. 251-254
Author(s):  
Yun Li He ◽  
Hai Peng Liu ◽  
Shi Qiao Gao ◽  
Cai Feng Wang
Keyword(s):  
Liquid Bridge ◽  
Capillary Condensation ◽  
Micro Structure ◽  
Macroscopic System ◽  
Kelvin Equation ◽  
Capillary Adhesion ◽  
Micromechanical Gyroscope ◽  
Capillary Phenomenon

In MEMS, the size of micro-structure is usually in the micron and even nanoscale. It's easier to form capillary phenomenon than the macroscopic system. In view of this phenomenon, this article is based on the micro-mechanical gyroscope as the research object, to analyze the occurrence of capillary condensation of adhesion phenomenon. Firstly, we derive the Kelvin equation for capillary condensation, and then combination of the Kelvin equation introduce the capillary condensation of the adhesion phenomenon; Secondly, it analyzes the dynamics characteristics of its structure existing the liquid bridge, and analyzes the causes of the liquid bridge; Finally, it analyzes the capillary adhesion phenomena on the performance of the micro-mechanical gyroscope,as well as how to avoid the generation of capillary condensation adhesion.

scholarly journals The sorption of vapours by ferric oxide gel. I.―Aliphatic alcohols

1934 ◽  
Vol 147 (860) ◽  
pp. 128-140 ◽  
Keyword(s):  
Ethyl Alcohol ◽  
Ferric Oxide ◽  
Adsorption Process ◽  
Capillary Condensation ◽  
Adsorbed Layer ◽  
Adsorbed Molecule ◽  
Complete Agreement ◽  
Condensation Process ◽  
Kelvin Equation ◽  
The Difference

In this paper isothermals of a series of alcohols on ferric oxide gel at 25°C are described. The sorption of methyl, ethyl, n. and iso-propyl, and n. butyl alcohols has been investigated in order to determine how the nature of the isothermal alters with the size of the adsorbed molecule. Isothermals of benzene and ethyl alcohol on ferric oxide gel have been described previously, and an examination of these data leads to the conclusion that the hysteresis phenomena are associated with a capillary condensation process which follows a true adsorption process on the surface of the pores. The application of the Kelvin equation to the calculation of the capillary radii at corresponding volumes gives the values 16 and 18 A respectively, from the benzene and alcohol isothermals. The lack of complete agreement may, of course, be due to the fact that the limit of validity of the equation has been reached, but there remains a possibility that the difference actually arises from the variation in the thickness of the adsorbed layer with the size of the adsorbed molecules. A similar conclusion was arrived at from an examination of the isothermals of methyl and ethyl alcohol on a specimen of silica gel which exhibits hysteresis, and the present series has therefore been determined in order to provide more extensive data for testing the validity of the Kelvin equation.

scholarly journals Van der Waals and Capillary Adhesion of Microelectromechanical Systems

2006 ◽  
Author(s):  
Frank W. DelRio ◽  
Maarten P. de Boer ◽  
Leslie M. Phinney ◽  
Chris J. Bourdon ◽  
Martin L. Dunn
Keyword(s):  
Microelectromechanical Systems ◽  
Capillary Condensation ◽  
Van Der Waals ◽  
Dispersion Forces ◽  
Surface Adhesion ◽  
Surface Separation ◽  
Capillary Adhesion ◽  
Close Proximity ◽  
Large Roughness ◽  
Deposition Technology

Interfacial adhesion is an important factor in determining the performance and reliability of microelectromechanical systems (MEMS). Van der Waals dispersion forces are the dominant adhesion mechanism in the low relative humidity (RH) regime. At small roughness values, adhesion is mainly due to van der Waals dispersion forces acting across extensive non-contacting areas and is related to 1/Dave2, where Dave is the average surface separation. These contributions must be considered due to the close proximity of the surfaces, which is a result of the planar deposition technology. At large roughness values, van der Waals forces at contacting asperities become the dominating contributor to the adhesion. Capillary condensation of water has a significant effect on rough surface adhesion in the moderate to high RH regime. Above a threshold RH, which is a function of the surface roughness, the adhesion jumps due to meniscus formation at the interface and increases rapidly towards the upper limit of Γ=2 γcos θ=144 mJ/m2, where γ is the liquid surface energy and θ is the contact angle.

Simple Universal Kelvin Equation Valid in the Critical Point Vicinity, External-Internal State Correction, and their Application to Nitrogen Capillary Condensation in Mesoporous Silica SBA-15

2018 ◽  
Vol 284 ◽  
pp. 801-806 ◽  
Author(s):  
Anton A. Valeev ◽  
Elena V. Morozova
Keyword(s):  
Experimental Data ◽  
Porous Medium ◽  
Phase Equilibrium ◽  
Mesoporous Silica ◽  
Critical Point ◽  
Capillary Condensation ◽  
Internal State ◽  
Curvature Radius ◽  
Universal Form ◽  
Kelvin Equation

A new simple universal form of the Kelvin equation, which can be used near the gas-liquid critical point and the correction of the pressure for vapor outside the porous medium are used for the N2 meniscus effective curvature radius calculation at the phase equilibrium in mesoporous silica SBA-15, on the basis of the capillary condensation experimental data.

Direct experimental verification of the Kelvin equation for capillary condensation

Nature ◽  
1979 ◽  
Vol 277 (5697) ◽  
pp. 548-549 ◽  
Author(s):  
L. R. FISHER ◽  
J. N. ISRAELACHVILI
Keyword(s):  
Experimental Verification ◽  
Capillary Condensation ◽  
Kelvin Equation
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