An improved meniscus surface model for contacting rough surfaces

Effects of gas adsorption isotherm and liquid contact angle on capillary force for sphere-on-flat and cone-on-flat geometries

“…Liquid menisci can be formed around the contact areas of two neighboring solid surfaces even at vapor pressures much lower than the saturation pressure (p sat ). Conventional continuum theories consider thermodynamic equilibria between the solid and the liquid surfaces (Young equation) and between the liquid and vapor phases (Young-Laplace and Kelvin equations) to predict the capillary force due to the meniscus [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. In these models, the liquid contact angle (h, often measured in the macroscale) and the characteristic Kelvin length (k K = cV m /R g T where c and V m are the liquid surface tension and molar volume, respectively; R g = 8.314 J/mol K; T = temperature; k K = typically in the range of 0.5-1.5 nm) are two key parameters controlling the size of the liquid meniscus and the magnitude of the capillary force at a given contact geometry and relative partial pressure of the vapor (p/p sat ).…”

“…In these models, the liquid contact angle (h, often measured in the macroscale) and the characteristic Kelvin length (k K = cV m /R g T where c and V m are the liquid surface tension and molar volume, respectively; R g = 8.314 J/mol K; T = temperature; k K = typically in the range of 0.5-1.5 nm) are two key parameters controlling the size of the liquid meniscus and the magnitude of the capillary force at a given contact geometry and relative partial pressure of the vapor (p/p sat ). Various elegant models have been developed to take into account the effects of solid surface roughness, liquid condensation, and evaporation kinetics [1,2,4,6,9,14,19,20].…”

Contact recording review

“…When the surfaces are considered as smooth, the intermolecular forces can be as large as 600 mN (Thornton 2003), and it could still be tens of mN even if surface roughness is considered (Hua et al 2007). In another viewpoint, the intermolecular force can also be studied by the approach of continuum-based modeling (Shi and Polycarpou 2008;Suh and Polycarpoua 2005;Xue and Polycarpou 2007), and both the adhesion force and the contact force are obtainable by their models. The continuum-based models consider not only the surface roughness, but also the elastic and plastic deformations.…”

Thermal protrusion induced air bearing frequency variations

“…The thermal protrusion is only generated when the read/write operations are conducted. Since the read/write operation time is only a very small amount of the working time of a hard disk drive, the durability and reliability of the hard disk drive can be significantly improved (Hua et al 2010;Xu et al 2007;Xue and Polycarpou 2007;Bhushan 1998).…”