Condensation phase transitions in bidisperse colloids
Physica A, (2005)Abstract
Condensation phase transitions in polydisperse colloids are studied
theoretically. For maximal simplification of calculations, a bidisperse
model of the system, consisting of relatively big and small particles,
is considered. Direct van der Waals interactions between big particles
as well as depletion forces between them due to small particles are
taken into account. The diagrams of "gas-liquid", "gas-solid"
and "liquid-solid" phase transitions in an ensemble of the big
particles are constructed. The influence of size and concentration
of small particles on the phase transitions is studied. Our results
show that increase in concentration of small particles leads to increase
in the initial temperature of the phase transition, i.e., the presence
of small particles stimulates the separation of the colloidal system
into two phases with different concentration of the big particles.
On the other hand, concentration of big particles, needed for the
phase transition, increases with the total concentration of small
particles. This factor makes realization of this phenomenon more
difficult.
