A General Framework for Liquid Marbles

TL;DR

This paper introduces a comprehensive analytical framework for liquid marbles, predicting their behavior during evaporation and aligning well with experimental data across diverse sizes and compositions.

Contribution

It develops a unified theoretical model for liquid marbles, accounting for various final states and matching experimental evaporation data over a wide range of conditions.

Findings

Final states include constant surface area, particle ejection, or multilayering.

Model accurately predicts evaporation behavior for particles from 7 nm to 300 μm.

Framework aids in designing liquid marble applications.

Abstract

Liquid marbles refer to liquid droplets that are covered with a layer of non-wetting particles. They are observed in nature and have practical significance. However, a generalized framework for analyzing liquid marbles as they inflate or deflate is unavailable. The present study fills this gap by developing an analytical framework based on liquid-particle and particle-particle interactions. We demonstrate that the potential final states of evaporating liquid marbles are characterized by one of the following: (I) constant surface area, (II) particle ejection, or (III) multilayering. Based on these insights, a single-parameter evaporation model for liquid marbles is developed. Model predictions are in excellent agreement with experimental evaporation data for water liquid marbles of particle sizes ranging from 7 nanometers to 300 micrometers (over four orders of magnitude) and chemical compositions ranging from hydrophilic to superhydrophobic. These findings lay the groundwork for the rational design of liquid marble applications.