1D roughness driven depinning of breath figures on PDMS

TL;DR

This paper investigates how surface roughness influences the self-assembly and pattern formation of droplets in breath figures on PDMS, revealing the dominant role of roughness over polymer type and analyzing the scale of constraint effects.

Contribution

It provides a semi-quantitative explanation for pattern formation influenced by surface constraints and determines the scale at which roughness impacts droplet organization.

Findings

Surface roughness significantly affects pore size and pattern formation.

Large scale patterns are composed of small droplets arranged inside distorted rings.

Roughness has a greater impact than polymer type on droplet organization.

Abstract

The influence of surface constraints on the self-assembly of liquid droplets is investigated. A semi-quantitative explanation for large scale pattern formation consisting of small scale closely arranged droplets inside the large scale distorted ring of droplets is presented in this paper. The scale at which the influence of constraints become dominant is also determined in this study. It is seen that the underlying roughness has a larger impact than the nature of polymer on pore size. Comparative studies of pore patterns formed on smooth and constrained substrates are reported. The simulated energy minimized shape of the droplets on smooth and constrained substrates are obtained using \textit{Surface Evolver}.