Review of Bubble Applications in Microrobotics: Propulsion, Manipulation, and Assembly

Abstract

In recent years, microbubbles have been widely used in the field of microrobots due to their unique properties. Microbubbles can be easily produced and used as power sources or tools of microrobots, and the bubbles can even serve as microrobots themselves. As a power source, bubbles can propel microrobots to swim in liquid under low-Reynolds-number conditions. As a manipulation tool, microbubbles can act as the micromanipulators of microrobots, allowing them to operate upon particles, cells, and organisms. As a microrobot, microbubbles can operate and assemble complex microparts in two- or three-dimensional spaces. This review provides a comprehensive overview of bubble applications in microrobotics including propulsion, micromanipulation, and microassembly. First, we introduce the diverse bubble generation and control methods. Then, we review and discuss how bubbles can play a role in microrobotics via three functions: propulsion, manipulation, and assembly. Finally, by highlighting the advantages and current challenges of this progress, we discuss the prospects of microbubbles in microrobotics.

Ultrahigh Efficient Collection of Underwater Bubbles by High Adsorption and Transport, Coalescence, and Collection Integrating a Conical Arrayed Surface

“…Currently, the collection and transport of underwater bubbles have received widespread attention from researchers. − The directional transport of underwater bubbles has important applications in multiple fields, ranging from scientific research to industrial production, such as catalytic reactions, , wastewater treatment, and underwater drag reduction . Functional surfaces with specific wettability have become important in controlling the motion of small bubbles.…”

“…Extensive research has been devoted to understanding the generation, growth, , aggregation, and detachment , of bubbles. The presence of a gas film can increase the adsorption of bubbles to hydrophobic interfaces, providing sufficient time for bubble growth and aggregation. , Surface wettability is determined by the interplay between the rough microstructures and the chemical composition of a surface. − Thus, it is possible to manipulate the adsorption force of bubbles to substrates through effective coordination of interfacial microstructures and chemical composition .…”

Meniscus-Induced Directional Self-Transport of Submerged Bubbles on a Slippery Oil-Infused Pillar Array with Height-Gradient

“…The directional manipulation of submerged bubbles is crucial for both theoretical research and industrial production, due to its potential applications in the fields of gas-involved electrochemistry, heat transfer, mineral flotation, organic degradation, and underwater microrobotics. − The superhydrophobic surface or lubricant-infused surfaces (LIPS) are usually used to achieve stable directional transport because of their excellent adhesion to bubbles. , According to the origin of driving force, current strategies for bubble transport are mainly classified into buoyancy assistance and wetting gradient force. The buoyancy assistance is characterized by the fact that no external energy input is required.…”

Review of bubble and magnetically driven catalytic micro/nanomotors: Fabrication and characterization

“…Bubble propulsion is one of the most significant motion mechanisms of MNMs. Many successful cases of MNMs whose propulsion mechanism is through the bubble recoil mechanism which produced from catalytic reactions have been reported in the literature [25]. Long-term durability and precise motion control make the Bubble-propelled MNMs with favorable biocompatibility and powerful driving force suitable candidates for medical applications.…”

“…Long-term durability and precise motion control make the Bubble-propelled MNMs with favorable biocompatibility and powerful driving force suitable candidates for medical applications. Most of these MNMs simultaneously use external energy sources such as magnetic field, acoustic wave, electric field, and light to boost propulsion and control movement [25,26].…”