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A technique for measuring contact angles at particles
Author(s) -
Bröckel Ulrich,
Löffler Friedrich
Publication year - 1991
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.19910080139
Subject(s) - wetting , contact angle , materials science , wetting transition , composite material , coating , texture (cosmology) , monolayer , porosity , phase (matter) , adhesive , nanotechnology , layer (electronics) , chemistry , organic chemistry , artificial intelligence , computer science , image (mathematics)
The behavior of particles at the phase transition between a gas or liquid and another liquid phase may be characterized by the so‐called wetting (or contact) angle. In contrast to plane surfaces, which allow such measurements to be conducted relatively easily, the determination of the wetting angle between a liquid and the surfaces of fine particles demands extensive preparative measures. The method adopted by Heertjes and Kossen [12] for example, involves compressing a tablet from the powder in question, from which the wetting angle may then be derived. The compression process naturally modifies the superficial structure of the particles, and hence their wetting characteristics. This paper describes a preparation technique with which the wetting angle between a liquid and fine particles can be derived without modifying the surface texture. This involves coating and adhering a monolayer of the powder on a carrier plate and measuring the composite wetting angle of the particles and the adhesive film. The specification of the adhesive's wetting angle and areal porosity of the carrier medium allows the wetting angle of the given powder subsequently to be evaluated.