Robotic dipping system for layer-by-layer assembly of multi-functional thin films

A simple, yet very flexible robotic dipping system for the preparation of functional thin films is presented. These films are deposited onto a substrate using the layer-by-layer assembly technique. The robot alternately dips a substrate into aqueous mixtures containing oppositely charged or otherwise complementary species. Samples can be spray rinsed (a unique feature of this robot relative to others created for thin film deposition) and blow dried after each dip. Dipping, rinsing, and drying times are adjustable and up to twelve mixtures can be deposited in any order. An example 20-bilayer film was prepared using aqueous mixtures of carbon black stabilized with polyethylenimine and poly(acrylic acid). This film exhibits low resistivity (<0.2 Ω·cm) and is free of the porosity and brittleness that are characteristic of highly filled polymer composites. The robotic dipping system is especially useful for films requiring more than tenbilayers and a variety of different layers.