Cellular-automata-based modeling of the electrostatic self-assembly (ESA) fabrication process

The electo-static self-assembly process (ESA) has proved to be extremely successful in creating multi-layer coatings with properties that can be tailored for particular applications. In this process, almost any surface with charged functional groups can be used as a substrate. Alternate dipping in solutions having ions of opposite charge builds up the layers through ionic bonding. One particular application of this process could be to form multi-functional bio-compatible coatings on MEMS devices intended for use in-vivo. In this paper, we describe two different models of the process based on cellular automata. The output of the models consists of three parameters as a function of layer: ionic coverage, film height and film roughness. The results of the models are compared to experimental data to determine which of them more accurately describes the ESA process.