Universality in coalescence of polymeric fluid drops

TL;DR

This paper reveals a universal pattern in the way polymeric liquid drops coalesce over time, regardless of polymer type or concentration, modeled effectively by a viscoelastic theory.

Contribution

It uncovers a universal temporal evolution of the coalescence neck radius across various polymers and concentrations, supported by high-speed imaging and viscoelastic modeling.

Findings

Universal scaling law for coalescence dynamics

Validation across multiple polymers and concentrations

Viscoelastic model accurately captures the behavior

Abstract

Coalescence of liquid droplets involves an interplay between capillary forces, viscous forces and inertial forces. Here, we unveil a universal temporal evolution of the neck radius during the coalescence of two polymeric drops. Through high speed imaging we demonstrate that drops of polyacrylamide (PAM), poly-vinyl alcohol (PVA), polyethylene oxide (PEO), polyethylene glycol (PEG) and xanthan gum (XG) depict a universal behavior $R/\sqrt(\nu_0\lambda) \sim (t/\lambda)^{0.36}(C/C^{*})^{-0.83}$ over a dilute, semi-dilute and non-dilute range of concentrations. A linear Phan-Thein-Tanner viscoelastic model captures the temporal aspect of universality.