Recent advances in bubble-based technologies: Underlying interaction mechanisms and applications

Gas bubbles widely exist in nature and numerous industrial processes. The physicochemical characteristics of bubbles such as large specific surface area, low density, and hydrophobicity make them an ideal platform for developing colloidal and interfacial technologies. Over the past few decades, much effort has been devoted to investigating the properties and behaviors of bubbles and their applications. A series of bubble-based technologies (BBTs) have been developed, which have attracted increasing attention and shown great importance in a wide range of engineering, material, and biological fields. These BBTs, such as bubble flotation and the bubble-liposome system, provide feasible and promising solutions to mineral separation, material assembling, medical diagnosis, and drug delivery. In this work, we have systematically reviewed the physicochemical characteristics of bubbles and how to modulate their behaviors in complex fluid systems, as well as the underlying fundamental interaction mechanisms of bubbles in related BBTs. Advanced nanomechanical techniques such as atomic force microscopy, which are used to quantify the interaction mechanisms in bubble-containing systems, have been introduced. The effects of various influential factors on the bubble behaviors are discussed, which provide potential approaches to improve the controllability and performance of BBTs. The recent advances in the applications of selected BBTs in engineering, biomedical, and material areas are presented. Some remaining challenging issues and perspectives for future studies have also been discussed. This review improves the fundamental understanding of characteristics and surface interaction mechanisms of bubbles, with useful implications for developing advanced BBTs.