Effect of Core Liquid Surface Tension on the Liquid Marble Shell

Abstract

Liquid marble is a non‐wetting droplet coated with micro‐ or nanometer sized particles and exhibits great versatility as a standalone system. Unique features such as low evaporation rate, low friction, and a porous shell enable it to be a potential tool for gas sensing, cell culture, and drug delivery. With the growing number of interests in these fields, it is important to understand the structure of the liquid marble shell and how it behaves with the variation of the surface tension of the core liquid. This paper investigates the thickness and the mass of liquid marble shell at various surface tension values. Surfactant mediated surface tension reduction allows the encapsulating particles to penetrate more into the core liquid and decreases the shell thickness. The shell thickness decreases significantly with the surface tension, whereas the mass remains almost constant. Interestingly, the trend reverses with further decrease of the surface tension. In this regime, both the thickness and the mass of the shell increase due to interfacial jamming. This work provides a new insight into understanding the contribution of the particle distribution at the shell for the stability and the measurement of the effective surface tension of a liquid marble.