Stiffness-guided motion of a droplet on a solid substrate

TL;DR

This study uses molecular dynamics simulations to explore how stiffness gradients on solid substrates can direct nanoscale droplet motion, revealing factors that enhance durotaxis such as gradient steepness, wettability, and droplet size.

Contribution

It provides new insights into nanoscale droplet durotaxis by systematically analyzing the effects of substrate stiffness gradient, wettability, and droplet size through molecular dynamics simulations.

Findings

Durotaxis is enhanced by increasing the stiffness gradient.

Higher substrate wettability improves directional motion.

Smaller droplets exhibit more pronounced durotaxis.

Abstract

A range of technologies require the directed motion of nanoscale droplets on solid substrates. A way of realizing this effect is durotaxis, whereby a stiffness gradient of a substrate can induce directional motion without requiring an energy source. Here, we report on the results of extensive molecular dynamics investigations of droplets on a surface with varying stiffness. We find that durotaxis is enhanced by increasing the stiffness gradient and, also, by increased wettability of the substrate, in particular, when droplet size decreases. We anticipate that our study will provide further insights into the mechanisms of nanoscale directional motion.