Towards a standardised metrology for multi-scale characterisation of nanostructured durable hydrophobic coatings

Nanostructured coatings are gaining an increasing importance in critical applications such as anti-fouling, low friction and boundary layer control applications, due to their ability to tailor roughness levels and to modify the energy of the underlying surface. The sustainability of a coating is linked to its lifetime and limited durability is one of the main drawbacks for nanostructured coatings. To improve performance and durability of nanostructured coatings a greater understanding of the structure at the nano-scale and the influence of this on the macro-scale behaviour is needed. As confirmation of this need, international bodies dealing with metrology standardisation have recognised that one of the main barrier limiting a larger scale exploitation of nanostructured coatings is the lack of understanding and testing methodologies able to link the nanostructure features of the coating with the final macro-scale performance of the coating itself. This paper will offer an overview on the potential of nanostructured coatings to provide engineering surfaces with durable hydrophobic/super-hydrophobic properties. The advancements achieved and the work carried out by TWI in this field will be illustrated. The project activities proposing the development and establishment of metrology methodologies for nanostructured coatings will be also mentioned. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)