Two-dimensional self-assembly of latex particles in wetting films on patterned polymer surfaces

The 2D self-assembly of micrometer-size latex particles in wetting films on patterned poly(dimethylsiloxane) (PDMS) polymer surfaces was studied. The dynamics of these processes were directly observed using an integrated zoom microscope and CCD camera. The direct observations revealed the particles are transported inside or toward the grooves of the pattern in the region where the liquid film is appropriately thin, and the particles self-assembly inside the grooves is caused by a lateral capillary force. Mechanisms for particle transportation and self-assembly are discussed.