Substrate elastic deformation due to vertical component of liquid-vapor interfacial tension

Young's equation is a fundamental equation in capillarity and wetting, which reflects the balance of the horizontal components of the three interfacial tensions with the contact angle (CA). However, it does not consider the vertical component of the liquid-vapor interfacial tension (VCLVIT). It is now well understood that the VCLVIT causes the elastic deformation of the solid substrate, which plays a significant role in the fabrication of the microfluidic devices because of the wide use of the soft materials. In this paper, the theoretical, experimental, and numerical aspects of the problem are reviewed. The effects of the VCLVIT-induced surface deformation on the wetting and spreading, the deflection of the microcantilever, and the elasto-capillarity and electroelasto-capillarity are discussed. Besides a brief review on the historical development and the recent advances, some suggestions on the future research are also provided.