Abstract
The vertical drying of a colloidal film containing rodlike particles was studied by means of kinetic Monte Carlo (MC) simulation. The problem was approached using a two-dimensional square lattice, and the rods were represented as linear -mers (i.e., particles occupying adjacent sites). The initial state before drying was produced using a model of random sequential adsorption (RSA) with isotropic orientations of the -mers (orientation of the -mers along horizontal and vertical directions are equiprobable). In the RSA model, overlapping of the -mers is forbidden. During the evaporation, an upper interface falls with a linear velocity of in the vertical direction and the -mers undergo translation Brownian motion. The MC simulations were run at different initial concentrations, , (, where is the jamming concentration), lengths of -mers (), and solvent evaporation rates, . For completely dried films, the spatial distributions of -mers and their electrical conductivities in both and directions were examined. Significant evaporation-driven self-assembly and orientation stratification of the -mers oriented along the and directions were observed. The extent of stratification increased with increasing value of . The anisotropy of the electrical conductivity of the film can be finely regulated by changes in the values of , , and .
3 More- Received 18 September 2016
DOI:https://doi.org/10.1103/PhysRevE.94.062803
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