A micrometer rod morphology was produced by self-assembly of poly(oxypropylene)amine (POP-amine) modified montmorillonite-The requisite primary structure was prepared by intercalation of the layered clay, with POP-amine, salts. During the drying process, the primary units self-assemble into micro-rods that are 100-800 nm wide and 2-40 mum long. The stacking process may involve two complimentary forces - the POP hydrophobic effect and the silicate ionic interaction - acting in separate directions.