A general model for dynamic contact angle over full speed regime

TL;DR

This paper introduces a new comprehensive model for dynamic contact angle that accurately fits data across a wide speed range and explains complex angle behaviors, advancing understanding of wetting dynamics.

Contribution

It presents a novel multi-scale and friction-based model that outperforms existing models in fitting dynamic contact angle data over extensive speed regimes.

Findings

Unprecedented fitting performance across five orders of magnitude in speed

Effective modeling of non-monotonous contact angle variations

Two key parameters are nearly predictable, with one correlating to viscosity.

Abstract

The prevailing models for advancing dynamic contact angle are under intensive debates, and the fitting performances are far from satisfying in practice. The present study proposes a model based on the recent understanding of the multi-scale structure and the local friction at the contact line. The model has unprecedented fitting performance for dynamic contact angle over wide spreading speed regime across more than five orders of magnitude. The model also well applies for non-monotonous angle variations which have long been considered as abnormal. The model has three fitting parameters, and two of them are nearly predictable at this stage. The one denoting the multi-scale ratio was nearly constant and the one representing the primary frictional coefficient, has a simple correlation with the liquid bulk viscosity.