title: Stability of a liquid bridge between nonparallel hydrophilic surfaces.
abstract: Formation of liquid bridges between two solid surfaces is frequently observed in industry and nature, e.g. in printing applications. When the two solid surfaces are not parallel (with a dihedral angle ψ between them), an interesting phenomenon emerges: if ψ exceeds a critical angle (denoted as ψc) the bridge is no longer stable, and propels itself toward the cusp of the surfaces. In this work we performed, for the first time, a systematic study on the parameters influencing ψcby combining experimental, theoretical, and numerical investigations. It was shown that ψcis determined by the advancing contact angle (θa) and Contact Angle Hysteresis (CAH) of the surfaces: it increases as θaor CAH increases, and these two parameters have a nonlinear and interdependent influence on ψc. Based on our quantitative results, an empirical equation is presented to predict the critical angle, ψc=f(θa,CAH) in closed analytical form. This equation can be used to calculate ψcfor bridges formed by moving down a pre-tilted surface towards a sessile drop on a stationary lower surface, or bridges between initially parallel surfaces which the top surface tilts after bridge formation.
authors.affiliation: Department of Mechanical Engineering, York University, Toronto, ON M3J 1P3, Canada.
authors.forename: Mohammadmehdi
authors.initials: M
authors.lastname: Ataei
authors.affiliation: Department of Mechanical Engineering, York University, Toronto, ON M3J 1P3, Canada.
authors.forename: Huanchen
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Mechanical Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada. Electronic address: ttang1@ualberta.ca.
authors.forename: Tian
authors.initials: T
authors.lastname: Tang
authors.affiliation: Department of Mechanical Engineering, York University, Toronto, ON M3J 1P3, Canada. Electronic address: alidad2@yorku.ca.
authors.forename: Alidad
authors.initials: A
authors.lastname: Amirfazli
keywords: Contact Angle Hysteresis; Liquid bridge; Nonparallel surfaces; Stability; Surface Evolver