The control of the thermocapillary assembly of colloidal particle clusters is
important for a variety of applications, including the creation of photonic
crystals for microelectronics and optoelectronics, membrane formation for
biotechnology, and surface cleaning for laboratory-on-chip devices. It is
important to understand the main mechanisms that influence the formation of
such clusters. This article considers a two-dimensional mathematical model
describing the transfer of particles by a thermocapillary flow in an unevenly
heated cell during the evaporation of a liquid. This gave us the opportunity to
study one of the main processes that triggers the formation of a particle
cluster. Whether the particle will move with the flow or stop at the heater,
becoming the basis for the cluster, is determined by the ratio between gravity
and the drag force. The results of numerical calculations show that, for small
particle concentrations, their fraction entering the cluster decreases as the
volumetric heat flux density
Q increases. The reason for this is an increase
in the thermocapillary flow with an increase in the volumetric heat flux
Q.
It reduces the probability of particles entering the cluster.