Numerical simulations of minimal meniscus size

In order to discuss issues raised before about the validity of macroscopic descriptions at nanometer scale, we use some numerical results dedicated to the description of nanomeniscus properties. Using numerical methods (lattice gas model and mean held density functional theories) Jang et al. studied the influence of RH on the pull-off force of a tip on a surface. They reproduced the behavior with a maximum observed with highly hydrophilic rounded tips surfaces (see section 9.3.1.1) and proposed other scenarios for different wetting conditions. 

Another issue of particular interest is the determination of the smallest size of a meniscus as a function of the tip geometry and the RH, which is relevant for the experimental results described before. Whatever the process involved, with a surface exhibiting an elastic-like behavior, the force at which the tip detaches from a surface, that is, the adhesion force measured, occurs when the tip reaches a critical contact area that corresponds to the smallest contact area between the tip and the meniscus. Therefore, the 

The numerical results show that the smallest size of the meniscus does not exhibit a monotonous, increasing, variation as a function of the vapor saturation (Fig. 9.8a). 

The variation of the meniscus minimum width shows accidents suggesting a more complicate evolution of the contribution of the capillary force as a function of RH. There is a balance between the feeding of the meniscus with increasing vapor saturation—thus 

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