Spreading Kinetics of Lubricant Droplets on Magnetic Recording Disks

Mate, C. Mathew

doi:10.1007/s11249-013-0171-5

Cited by 27 publications

(21 citation statements)

References 48 publications

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“…Marchon and Karis [12] and Mate [14,20] used this disjoining pressure for the analysis of the spreading behavior of a steplike boundary of a non-polar lubricant film although the former researchers usually used the simpler disjoining pressure without considering d 0 [7][8][9][10][11]. Although a detailed derivation process of this equation is not known, Π c1 always takes a positive value when A > 0.…”

Section: Disjoining Pressure Derived From Attractive Term In Ljpmentioning

confidence: 99%

“…r 0 = 0.637r 0 (14) This is the relationship between the molecular equilibrium distance r 0 in the LJP and mean vdW distance d 0 between the liquid film and solid surface. Note that without this relationship, the disjoining pressure Π t in Equation (13) takes a constant value even at infinite liquid thickness.…”

Section: Disjoining Pressure Derived From Ljpmentioning

confidence: 99%

“…When Equation (14) holds, the disjoining pressure Π s2 including both attractive and repulsive terms becomes, from Equation (12),…”

Section: Disjoining Pressure Derived From Ljpmentioning

confidence: 99%

“…Substituting Equation 18into Equation (21) and integrating it, we can obtain the flow velocity u. In the experimental and theoretical investigation of spreading kinetics of a small droplet in the submonolayer thickness regime, Mate [14,20] found that spreading profiles can be evaluated by the Poiseuille flow model without slip at the solid surface. Therefore, by determining the integral constant to satisfy the no-slip condition at the solid surface, we obtain the velocity in the following form:…”

Section: Derivation Of the Diffusion Equationmentioning

confidence: 99%

“…Mate [14] investigated the spreading kinetics of PFPE lubricant nanodroplets with 0-8 hydroxyl functional groups on a carbon-coated magnetic disk surface. He found that when the central droplet dissipates into a pancake-shaped film, the spreading profile is well described by a diffusion equation derived from the Poiseuille flow model with zero slip for Fomblin-Z and Z-dol lubricants if the unknown viscosity is identified experimentally.…”

Section: Introductionmentioning

confidence: 99%

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Disjoining Pressure Derived from the Lennard–Jones Potential, Diffusion Equation, and Diffusion Coefficient for Submonolayer Liquid Film

Ono

2018

Surfaces

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In magnetic hard disk drives, it is important to evaluate the replenishment effect of a submonolayer lubricant film under a more severe condition that the head–disk spacing has to be reduced from the current 0.7 nm to ~0.5 nm. In contrast to the prevailing conventional diffusion equation validated for multilayer liquid film, the author has already proposed a new diffusion equation more suitable for submonolayer film by intuitively incorporating the density reduction effect in the submonolayer liquid film. This paper presents a rigorous derivation of the disjoining pressure (DP) from Lennard–Jones potential (LJP) and formulated the diffusion equation incorporating the DP. The difference in the rigorous DP and diffusion equation from the previous versions is negligibly small except in a small film thickness less than the van der Waals (vdW) distance. The theoretical relationship between the vdW distance in the DP and the molecular force equilibrium distance in the LJP is elucidated. Rigorous derivations of the DP and diffusion equation for multilayer liquid film from the LJP are also presented. The superiority of the submonolayer diffusion equation over the conventional equation in the submonolayer film regime is demonstrated by comparing their theoretical diffusion coefficients with Waltman’s experimental data.

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