Square arrays of microfibers attached to a substrate form highly ordered patterns of 2x2 fiber clusters (tetramers) under the influence of capillary forces at the surface of an evaporating liquid droplet. This pattern formation is modeled as an irreversible sequential adsorption process on a square lattice, in which interacting tetramers form sequentially on an initially empty lattice, giving rise to extended spatial correlations. The model reproduces several features of the observed patterns of spatial tetramer organization.

Sequential Adsorption Model of Microfiber Clustering

Jayson Paulose, David R. Nelson, and Joanna Aizenberg

SEM image of a region of epoxy microfibers with tetramer clusters induced by ethanol evaporation.

50 μm

Tetramer spatial correlations from sequential adsorption model compared with experiment.

Harvard MRSEC DMR-0820484 D.A. Weitz and C.M. Friend