Authors: H.J. Choi, J.Y. Kim, S.D. Hong, M.Y. Ha, and J. Jang
Affilation: Pusan National University, Korea
Pages: 693 - 696
Keywords: water meniscus, capillary force, adhesion, AFM, molecular dynamics simulation, density profile, contact angle
Under ambient humidity, water condenses as a meniscus between an atomic force microscope (AFM) tip and a surface, giving rise to a strong capillary force on the tip. We performed a molecular dynamics simulation of the nano-confined water meniscus. We studied the effects of the tip and surface hydrophilicity on the meniscus structure. By changing the tip-surface distance, we have simulated the formation, shrinkage, and breakage of the water meniscus. The nanometer meniscus substantially fluctuates in its periphery due to its instability, in agreement with our previous lattice gas simulation. We obtained the density profile and contact angle of the meniscus. By using these structural parameters, we calculated the capillary force between the tip and surface. Our calculation reproduced the typical behavior of the experimental force-distance curve.