Diffusive growth of a single droplet with three different boundary conditions
Department of Mathematical Sciences, Brunel University,
Uxbridge, Middlesex, UB8 3PH, UK
Published online: 15 March 2000
We study a single, motionless three-dimensional droplet growing by adsorption of diffusing monomers on a 2D substrate. The diffusing monomers are adsorbed at the aggregate perimeter of the droplet with different boundary conditions. Models with both an adsorption boundary condition and a radiation boundary condition, as well as a phenomenological model, are considered and solved in a quasistatic approximation. The latter two models allow particle detachment. In the short time limit, the droplet radius grows as a power of the time with exponents of 1/4, 1/2 and 3/4 for the models with adsorption, radiation and phenomenological boundary conditions, respectively. In the long time limit a universal growth rate as is observed for the radius of the droplet for all models independent of the boundary conditions. This asymptotic behaviour was obtained by Krapivsky  where a similarity variable approach was used to treat the growth of a droplet with an adsorption boundary condition based on a quasistatic approximation. Another boundary condition with a constant flux of monomers at the aggregate perimeter is also examined. The results exhibit a power law growth rate with an exponent of 1/3 for all times.
PACS: 64.70.Fx – Liquid-vapor transitions / 64.60.Qb – Nucleation / 68.45.Da – Adsorption and desorption kinetics; evaporation and condensation
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000