posted on 2023-09-14, 22:13authored byJan Nicklas, Lisa Ditscherlein, Urs A. Peuker
The dynamics of the
three-phase contact line during particle–bubble
interactions determine the stability of particle–bubble aggregates
in flotation. The interaction of particles and sessile gas bubbles
can be studied by colloidal probe atomic force microscopy (CP-AFM).
This paper demonstrates a method to obtain the contact angle, the
position of the three-phase contact line on the particle, and the
bubble profile by utilizing the full information contained in AFM
force–distance curves, i.e., force and CP-position information
as well as the work done to move the three-phase contact line on the
CP-particle. The proposed method does not require any assumption of
a constant contact angle or a constant opening angle. This is achieved
by the combined solution of the particle force balance and an expression
for the work required to move the three-phase contact line over the
colloid probe. The applicability to AFM force–distance measurements
was demonstrated for the interaction of a hydrophobic SiO2 or a hydrophobic Al2O3 colloidal probe particle
with sessile gas bubbles having radii between 45 and 80 μm.