Fundamentals and Applications of Electrowetting: A Critical Review

We have witnessed rapid and exciting development in electrowetting (EW) or electrowetting-on-dielectric (EWOD) since 1990s. Owing to its great advantages such as easy operation, sensitive response and electrical reversibility, EW has found many applications in various fi elds, especially in micro- and nano-fl uidics, electronic display, etc. The aim of this review is to inspire new investigations on EW, not only in theory and numerical simulation, but also in experiments, and spur further research on EW for more practical applications. A comprehensive review is presented on the EW research progress, and experiments, theoretical modeling and numerical simulations are covered. After a brief look at the development history, some latest experimental and simulation methods, such as Lattice Boltzmann method, phase-fi eld method and molecular dynamics (MD), are introduced. Some representative practical applications are then presented. Unresolved issues and prospects on EW as the fi nal part of this review are expected to attract more attention and inspire more in-depth studies in this fascinating area. Young (L-Y) equation, curvature effect, elasto-electro-capillarity (EEC), Lattice Boltzmann method (LBM), phase-fi eld model, molecular dynamics (MD) simulations, coffee stain ring, electronic display, liquid lens, Micro Total Analysis Systems (μ-TAS), cell-based digital microfl uidics