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Download fileHysteresis of the contact angle of a meniscus inside a capillary with smooth, homogeneous solid walls
journal contribution
posted on 2016-08-16, 10:41 authored by I. Kuchin, Victor StarovA theory of contact angle hysteresis of a
meniscus inside thin capillaries with smooth, homogeneous solid walls is developed in terms of surface forces (disjoining/
conjoining pressure isotherm) using a quasi-equilibrium approach. The disjoining
/conjoining pressure isotherm includes electrostatic, intermolecular, and structural components. The values of the static receding θr, advancing θa , and
equilibrium θe contact angles in thin capillaries were calculated on the basis of the shape of the disjoining/conjoining pressure isotherm. It was shown that both advancing and receding contact angles depend on the capillary radius. The suggested
mechanism of the contact angle hysteresis has a direct experimental confirmation: the process of receding is accompanied by the formation of thick β-films on the capillary walls. The effect of the transition from partial to complete wetting in thin capillaries is predicted and analyzed. This effect takes place in very thin capillaries, when the receding contact angle decreases to zero.
Funding
This research was supported by the Engineering and Physical Sciences Research Council, U.K.; the CoWet Marie Curie ITN project, EU; the COST MP1106 project and MAP EVAPORATION project, European Space Agency; and COST MP 1106, EU.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Chemical Engineering