Wetting and spreading: Fundamental theories to cutting-edge applications

Wetting and spreading are familiar phenomena in nature and commonly observed in our daily life, and of great significance for basic scientific researches as well as providing solutions to the cutting-edge technical applications. Recent decades, learning from Nature, unique wetting and spreading behaviors have been biomimetically realized through the construction of artificial materials, which have promoted the ongoing development of relating areas like the liquid transportation, spraying, cleaning, and painting in industry and agriculture, and even influenced the way of our daily life. A systemic and timely review is therefore necessary to summary the existing novel researches and provide some idea of the next tide in leading the scientific trend. Here, we will present how the bio-inspired materials with special wettabilities have been integrated into traditional materials or devices to improve their wetting and spreading performances. The progresses of both fundamental theories and cutting-edge applications that reported in recent years are briefly reviewed. Basing on the impacting state of the liquid, the wetting and spreading progresses have been divided into 3 categories: which include interaction between the solid surfaces with the static contacting drop, dynamic impacting drop, and overflowing fluid. At the end of the review, some challenges and development tendency of the ongoing wetting and spreading research are highlighted.