Molecular ordering of precursor films during spreading of tiny liquid droplets

TL;DR

This study investigates the microscopic structure and ordering of precursor films during the spreading of tiny liquid droplets on solid surfaces, revealing persistent local order influenced by molecular interactions.

Contribution

It introduces a molecular dynamics model for droplet spreading that highlights the formation of ordered precursor films and their dependence on molecular interactions.

Findings

Precursor films can exhibit high local order.

Order persists even in flexible chain molecules.

Structural information can reveal molecular interactions.

Abstract

In this work we address a novel feature of spreading dynamics of tiny liquid droplets on solid surfaces, namely the case where the ends of the molecules feel different interactions to the surface. We consider a simple model of dimers and short chain--like molecules which cannot form chemical bonds with the surface. We study the spreading dynamics by Molecular Dynamics techniques. In particular, we examine the microscopic structure of the time--dependent precursor film and find that in some cases it can exhibit a high degree of local order. This order persists even for flexible chains. Our results suggest the possibility of extracting information about molecular interactions from the structure of the precursor film.