Bubble‐Induced In Situ Property Modulation of Liquid Metal

Abstract

Alterable surface tension and electrical properties of liquid metals are of great significance to their applications in intelligent robots, bionic applications, and electronics. To further understand the interfacial properties of liquid metals, the highly effective and in situ modulation strategy is imperative to be developed. Here, a bubble‐induced in situ modulation strategy to achieve the on‐demand surface tension and electrical properties is initially demonstrated. The size and shape of bubbles are modulated by virtue of thermal effect under the laser irradiation. As a consequence of the regulated location of bubbles, the surface tension and electrical potential are in situ adjusted reversibly and periodically. In situ surface property modulation of liquid metal may provide promising prospects for efficient property tuning strategies and innovative on‐demand applications.

Mechanism of Oil-in-Liquid Metal Emulsion Formation

“…For example, LM readily breaks up into microdroplets when mixed with a similar volume of another liquid (e.g., silicone oil). − Smaller volumes of air, , silicone oil, water, peroxide, hydrochloric acid, and sodium hydroxide , can be directly injected into a larger pool of LM but rapidly escape due to large buoyancy forces. Interestingly, the environment above the LM pool can be adjusted to promote or inhibit oxide or surfactant “shell” formation and trap either very small (∼5–10 μm) or very large (∼1 cm) droplets of several fluids right under the external LM surface. , However, these neat fluidic structures are restricted to the surface region or are temporary, so they are of limited use in practical applications. In contrast, silicone oil with a viscosity below ∼1000 cSt can be manually dispersed into microscale droplets (∼5–500 μm) within LM foams to create lasting emulsions .…”

“…43−46 Smaller volumes of air, 47,48 silicone oil, water, peroxide, hydrochloric acid, and sodium hydroxide 48,49 can be directly injected into a larger pool of LM but rapidly escape due to large buoyancy forces. Interestingly, the environment above the LM pool can be adjusted to promote or inhibit oxide or surfactant "shell" formation and trap either very small (∼5−10 μm) 50 or very large (∼1 cm) droplets of several fluids right under the external LM surface. 48,49 However, these neat fluidic structures are restricted to the surface region or are temporary, so they are of limited use in practical applications.…”

Atomic engineering of two-dimensional materials via liquid metals

“…Using liquid metal in preparing self-aligned 2D materials exhibit unique superiorities including high surface tension, 208 reconfigurability, conformal contact, and facile processing. Liquid metals, such as Ga-based alloys, possess high surface tension, allowing them to form smooth and stable liquid surfaces.…”

Reconfigurable Liquid‐Bodied Miniature Machines: Magnetic Control and Microrobotic Applications

“…[115] One of the critical factors in controlling liquid metal-based machines is the driving force of the miniature soft devices. Various driven mechanisms have been proposed, including selfpropulsion (e.g., bubble propulsion, [116][117][118][119] self-electrophoretic propulsion, [120][121][122][123][124][125] enzyme-powered robots [126,127] ), Marangoni effect-based locomotion, [128][129][130] and external fields-driven navigation (e.g., magnetic field, [131][132][133][134] electric field, [135][136][137][138][139][140][141][142] ultrasound, [143,144] light [145][146][147] ). Magnetically driven liquid metal-based robots are usually driven by permanent magnets or electromagnets.…”