Liquid Marble as an Amphibious Carrier for the Controlled Delivery and Release of Substances

Abstract

The motion control of small objects has received significant interest in the research field of soft active matter. Controlling the release of substances from small objects has also attracted attention in other fields, such as the agrochemical and biomaterial fields. Until now, these two research objectives have been conducted independently in most cases but have the same ultimate goal: to transport small objects loaded with functional substances in a controlled manner and to release the substances at a desired time within the same system. This Perspective aims to highlight the challenges for realizing both the amphibious motion control of objects and the controlled release of substances by the application of external stimuli within the same system, using liquid marbles, which are particle-layer-coated small droplets, as a carrier.

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

“…The LM is a promising candidate as a carrier for such objects because of easy fabrication and handling. 75 Here, we demonstrate the transport of the LMs on planar air−water surface, followed by the on-demand release of their inner liquids to detect the presence of acid in the supporting bulk aqueous phase (Figures 1c and 8). To this aim, we fabricated the LM containing an aqueous solution of methyl orange (0.1 wt %, 10 μL) as a pH indicator using BA/ PPy particles as a stabilizer.…”

“…The controlled delivery and on-demand release of small amounts of reactants within the same system has received significant interest. The LM is a promising candidate as a carrier for such objects because of easy fabrication and handling . Here, we demonstrate the transport of the LMs on planar air–water surface, followed by the on-demand release of their inner liquids to detect the presence of acid in the supporting bulk aqueous phase (Figures c and ).…”

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).…”

Nonspherical Epoxy Resin Polymer Particles Synthesized via Solvent-Free Polyaddition Reactions

“…Liquid droplets stabilized in air by adsorption of hydrophobic solid particles on the droplet surface are called liquid marbles (LMs). − Since the LMs are covered by solid particles, the liquid can be treated as a soft solid. Recently, LMs have attracted increasing interest because of their potential for use as miniature reactors, ,− sensors, − microcentrifuges, microfluidics, collision-based computing devices, and material carriers. − Various solid particles, including lycopodium, silica particles, polytetrafluoroethylene (PTFE) particles, and polystyrene particles, have been used as stabilizers for LMs. Most of the stabilizers are spherical or have ill-defined shapes, and their ill-defined aggregates are often adsorbed on the droplet surfaces as LM stabilizers.…”