Switchable Opening and Closing of a Liquid Marble via Ultrasonic Levitation

Abstract

Liquid marbles have promising applications in the field of microreactors, where the opening and closing of their surfaces plays a central role. We have levitated liquid water marbles using an acoustic levitator and, thereby, achieved the manipulation of the particle shell in a controlled manner. Upon increasing the sound intensity, the stable levitated liquid marble changes from a quasi-sphere to a flattened ellipsoid. Interestingly, a cavity on the particle shell can be produced on the polar areas, which can be completely healed when decreasing the sound intensity, allowing it to serve as a microreactor. The integral of the acoustic radiation pressure on the part of the particle surface protruding into air is responsible for particle migration from the center of the liquid marble to the edge. Our results demonstrate that the opening and closing of the liquid marble particle shell can be conveniently achieved via acoustic levitation, opening up a new possibility to manipulate liquid marbles coated with non-ferromagnetic particles.

Droplet Drying Patterns on Solid Substrates: From Hydrophilic to Superhydrophobic Contact to Levitating Drops

“…However, the droplet levitation technology is a promising candidate for generating novel applications. For example, the technique of manipulating levitated drops used on liquid marbles [287] may be applied to insert desired components in dried shell structures [66] for drug delivery or other applications.…”

On‐Demand Coalescence and Splitting of Liquid Marbles and Their Bioapplications

“…[31,32] In addition, acoustic levitation strategy has been applied to realize the manipulation, and the opening and closing of the levitated LMs could be achieved from variation of the sound intensity and frequency. [33,34] However, such a method is irreversible, power consuming, and generally limited to light and small LMs. The sustained shaking of the LMs is inevitable, which may interfere the inner liquid reactions especially for the cell activities in the biomedical applications.…”

Light‐Driven Transport of a Liquid Marble with and against Surface Flows

“…[7,8] This result led to intense research to manipulate and understand the hydrodynamic behavior of these new entities. [9,10] However,although alot of progress has been made in the design and comprehension of liquid marbles,reported studies on their actuation have been limited to only af ew cases.A typical strategy involves the use of stimuli-responsive particles,i ncluding photosensitive [11,12] and magnetic [13][14][15] particles suspended in or coating the marble,m aking remote actuation possible but making each strategy specific to the composition of the liquid marble.C omposition-independent approaches were restricted to the use of electric [8,16,17] or ultrasonic [18] stimulation but, in these cases,l ong-range and precise transport could not be achieved. Photoactuation thus appears as ap romising alternative offering contactless, tunable,a nd highly resolved stimulation.…”