Automatic film formation system for ultra-thin organic heterostructure by mass-controlled layer-by-layer sequential adsorption method within one nanometer interface roughness

An automatic film formation system using an enhanced mass-controlled layer-by-layer sequential adsorption process was newly developed for the fabrication of ultra-thin organic films formed by various polymers, monomers, and inorganic materials. This technique can be applied to both water solutions and volatile solvents. In this process, a quartz crystal microbalance (QCM) was attached to the arm of a robot and the frequency shifts during the adsorption of the materials were monitored. By feeding back the data acquired by the QCM from the deposition to the dipping time, a high quality self-assembly film was produced. As a result, the interface roughness between the layers can be controlled within one nanometer. The cross-sectional TEM (transmission electron microscopy) observation of the films formed by the conventional time controlled dipping method and the newly established mass-controlled dipping method reveals that the interface of the heterostructure of the latter was much smoother than the former. In addition, this automatic dipping system can be applied not only for polyelectrolytes, but also for inorganic materials.