Non-wettable surfaces – From natural to artificial and applications: A critical review

Non-wettable surfaces have recently attracted significant attention due to their enormous promising applications. These applications are primarily due to their ability to repel liquid drops and remain unwetted. In this review, the various names used in describing non-wettable surfaces are given. This is followed by the fundamental theories of wetting. Natural non-wettable surfaces are then considered, along with their importance. Thereafter, we discuss how artificial non-wettable (biomimetic) surfaces are prepared. Next, the basic properties of non-wettable surfaces, which make them promising candidates for a wide range of applications, are discussed. Furthermore, the various applications of non-wettable surfaces are discussed, with references made to review articles with specific coverage of named applications. We conclude with a summary, challenges limiting the application of non-wettable surfaces to some real-life situations and possible suggestions to mitigate them as well as opportunities for future work.