Liquid Marbles under Electric Fields: New Capabilities for Non-wetting Droplet Manipulation and Beyond

Abstract

The study of liquid marbles (LMs) composed of stabilizing liquid droplets with solid particles in a gaseous environment has matured into an established area in surface and colloid science. The minimized "solid−liquid−air" triphase interface enables LMs to drastically reduce adhesion to a solid substrate, making them unique non-wetting droplets transportable with limited energy. The small volume, enclosed environment, and simple preparation render them suitable microreactors in industrial applications and processes such as cell culture, material synthesis, and blood coagulation. Extensive application contexts request precise and highly efficient manipulations of these non-wetting droplets. Many external fields, including magnetic, acoustic, photothermal, and pH, have emerged to prepare, deform, actuate, coalesce, mix, and disrupt these non-wetting droplets. Electric fields are rising among these external stimuli as an efficient source for manipulating the LMs with high controllability and a significant ability to contribute further to proposed applications. This Feature Article attempts to outline the recent developments related to LMs with the aid of electric fields. The effects of electric fields on the preparation and manipulation of LMs with intricate interfacial processes are discussed in detail. We highlight a wealth of novel electric field-involved LM-based applications and beyond while also envisaging the challenges, opportunities, and new directions for future development in this emerging research area.

Aqueous Bubbles Stabilized with Millimeter-Sized Polymer Plates

“…In the PET, PET-C, and PET-F plate systems, the plates adsorbed to the air–water interface for all sizes and solid concentrations, and bubbles were stabilized in water media after the plates, water, and air were mixed in the glass vial (Figure S4a–c). It is worth noting that some liquid marbles, − water droplets coated by plates in the air phase, were also occasionally formed in the case of the PET-F plate system (Figure S5). On the contrary, in the PET-S plate system, no or few bubbles were generated under all conditions examined in this study, and most of the plates remained in the water media and settled to the bottom of the vial (Figure S4d).…”

Photo- and Thermoresponsive Liquid Marbles Based on Fatty Acid as Phase Change Material Coated by Polypyrrole: From Design to Applications

“…Liquid marbles (LMs) are liquid droplets stabilized with hydrophobic solid particles adsorbed to gas–liquid interface in gaseous environment. − The general size of LMs is millimeter, and the LM can move easily both on solid and liquid surfaces. The particle layer adsorbed at gas–liquid interface can prohibit direct contact between the internal liquids of the LMs and can work as an armor to prevent coalescence of individual LMs.…”

Preprogramming Floating Time of Liquid Marble

“…[ 15 ] The direction (i) is approached by the synthesis and/or interfacial design of responsive particles for liquid marbles. [ 14 ] Various responsive liquid marbles have been reported including those response to light, [ 16 ] electricity, [ 17 ] magnet, [ 18 ] temperature, [ 19 ] ultrasound, [ 20 ] chemical vapor [ 21 ] or pressure. [ 22 ] Even multi‐responsive liquid marbles have been achieved by the integration of several functional particles on the liquid marbles.…”