Nanodroplet Depinning from Nanoparticles

by Qi Liu, Fong Yew Leong, Zainul Aabdin, Utkarsh Anand, Tran Si Bui Quang, and Utkur Mirsaidov

ACS Nano, Article ASAP DOI: 10.1021/acsnano.5b03078
Publication Date (Web): August 18, 2015

Nanoscale defects on a substrate affect the sliding motion of water droplets. Using in situ transmission electron microscopy imaging, we visualized the depinning dynamics of water nanodroplets from gold nanoparticles on a flat SiNx surface. Our observations showed that nanoscale pinning effects of the gold nanoparticle oppose the lateral forces, resulting in stretching, even breakup, of the water nanodroplet. Using continuum long wave theory, we modeled the dynamics of a nanodroplet depinning from a nanoparticle of comparable length scales, and the model results are consistent with experimental findings and show formation of a capillary bridge prior to nanodroplet depinning. Our findings have important implications on surface cleaning at the nanoscale.

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