To study the properties of films produced by spin-assisted layer-by-layer (LBL) assembly, researchers from the Univ. of Michigan, Ann Arbor, Mich., invented the Spin-Grower Desktop Layer-by-Layer Assembly System, which enables rapid and automated synthesis of nanostructured thin films by spin-assisted LBL assembly. The conventional method of LBL assembly is by dip coating; a substrate is immersed in a series of oppositely-charged solutions. The Spin-Grower performs LBL assembly by spinning the substrate rapidly while alternating compounds are delivered one layer at a time. Because of the centrifugal and viscous forces acting on the liquid compounds, molecules adhere to the substrate much faster than in the dipping process. Layers can be created in a matter of seconds, thus reducing production times by an order of magnitude and creating the potential for thicker multilayer composites with new morphologies and properties.
Built with off-the-shelf components combined with some hand-crafted parts, the Spin-Grower prototype grew a film of high-quality aligned nanocomposites to 300 bi-layers within hours (as compared to days). The Spin-Grower is fully automated and accommodates substrates with diameters up to 6 inches.