# 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.

## Key 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.

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Source: https://tomesphere.com/paper/1904.12358