Growth/Dissolution. The driving force is here a difference in the
chemical potential between the substance making up the particle and the
same substance in solution. If the solution isundersaturated the particles will
dissolve, whereas if it issupersaturated the particles can grow. For new
particles to form, nucleation is needed (Chapter 14). Growth of solid
particles generally means crystallization, a complicated phenomenon
(Chapter 15). We will not further discuss this type of change in the
present chapter.
Ostwald Ripening. The driving force is the difference in chemical
potential of the material in particles differing insurface curvature, as given
by the Kelvin equation (Section 10.5.3).
FIGURE13.1 Illustration of the various changes in dispersity. S¼solid, L¼liquid,
and G¼gaseous particle./possible in some cases.:enhances, (:) may be
slightly enhancing, and;impedes the change. The solid lines in the particles in (e)
denote (fat) crystals.