Ultrafast Spontaneous Motion of Nanodroplets
Abstract
Making liquid droplets move spontaneously on solid surfaces is a key challenge in lab-on-chip and heat exchanger technologies. The best-known mechanism, a wettability gradient, does not generally move droplets rapidly enough and cannot drive droplets smaller than a critical size. Here we report how a curvature gradient is particularly effective at accelerating small droplets, and works for both hydrophilic and hydrophobic surfaces. Experiments for water droplets on tapered surfaces with curvature radii in the sub-millimeter range show a maximum speed of 0.28 m/s, two orders of magnitude higher than obtained by wettability gradient. We show that the force exerted on a droplet scales as the surface curvature gradient. Using molecular dynamics simulations, we observe nanoscale droplets moving spontaneously at over 100 m/s on tapered surfaces.
Keywords
Cite
@article{arxiv.1205.6141,
title = {Ultrafast Spontaneous Motion of Nanodroplets},
author = {Cunjing Lv and Chao Chen and Yin-Chuan Chuang and Fan-Gang Tseng and Yajun Yin and Francois Grey and Quanshui Zheng},
journal= {arXiv preprint arXiv:1205.6141},
year = {2015}
}
Comments
18 pages, 6 figures. arXiv admin note: substantial text overlap with arXiv:1202.6582