1 Influence of Gravity on the Sliding Angle of Water Drops on Nanopillared Superhydrophobic Surfaces Hao Li* ,a,c , Tianyu Yan b , Kristen A. Fichthorn*, b a School of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao, 266590, China b Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States c National Engineering Laboratory of Offshore Geophysical and Exploration Equipment, China University of Petroleum, Shandong, 266580 Keywords: Molecular dynamics simulation, sliding angle, contact angle, superhydrophobic surface ABSTRACT: Molecular dynamics (MD) simulations were used to study the effects of gravity, solid surface energy, and fraction of water-solid interface area on water droplet sliding angles on nanopillared surfaces. To effectively simulate the influence of gravity on drop sliding, we developed a protocol in which we scale the value of gravitational acceleration used in our simulations according to the Bond number (Bo). In this way, we approximate the behavior of