How to exploit the full potential of the dip-coating process to better control film formation

Abstract

Dip-coating is an ideal method to prepare thin layers from chemical solutions since it is a low-cost and waste-free process that is easy to scale up and offers a good control on thickness. For such reasons, it is becoming more and more popular not only in research and development laboratories, but also in industrial production, as testified by the increasing number of annual publications (9, 180, and 480 articles in 1990, 2000, and 2010, respectively). Even so, the full potential of dip-coating has not yet been fully explored and exploited. This article highlights the recent progresses made by tuning the processing conditions beyond conventional ranges to prepare more and more complex and controlled nanostructured layers. Especially, we will see how one can take advantage of an accurate tuning of the withdrawal speed and of the atmosphere to control the nanostructuration originating from evaporation-induced-self-assembly (EISA), together with the final thickness from a few nm up to 1 μm from the same initial solution. A new regime of deposition, involving capillary induced convective coating that is highly suitable for the deposition from aqueous and/or highly diluted solutions, will be described. Finally, it will be demonstrated that dip-coating is also a well suited method to impregnate porosity, to make nanocomposites, or to perform nanocasting. The present discussion is illustrated with systems of interests in domains such as optics, energies, nanoelectronics, nanofluidics, etc.