Superhydrophobic, Superslippery, Nanopatterned Metallic and Polymeric Surfaces

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The goals of this research proposal are the development of a fast production technique using laser femtosecond ablation for nanopatterning various metallic and polymeric substrates and the optimization of the morphology of metallic and polymeric surfaces in order to identify the optimum surface morphology that results maximum superhydrophobicity and superoleophobicity. Our previous developments in the area of manufacturing superhydrophobic substrates were slow and inefficient in scanning relatively large areas, and these are needed to demonstrate potential applications i.e. construction of flow channels with superslippery interfaces, biomedical devices and tools such as surgical tools. The method developed in our lab is a new method for surface roughening, essentially is ablation with short-pulse laser on metals and tough polymers (Kietzig et al., Langmuir, 2009). Exposure of the surface to CO2 renders the surface superhydrophobic, a remarkable discovery. The main objective to make this manufacturing technique faster by laser splitting so that we can produce substrates of relatively large areas. Such interfaces are self-cleaning and extremely useful in medical devices and tools whereas superhydrophobic polymers are biocompatible with human tissues and therefore the targeted application will be in the biomedical engineering field such as surgical tools, medical implants, and blood vessel replacement. Another application equally important and part of this proposal is polymer rheology and processing where the use of superhydrophobic surfaces for the construction of dies are expected to render polymer operations extremely efficient in both the rate of production and energy consumption. As known, polymer processes exhibit many instabilities that limit the rate of production to low rates. Such nanopatterned interfaces would change dramatically the boundary conditions applicable to their flow (super-slippery) dramatically reducing the pressure drop. However, the relationship between superhydrophobicity and slip is not known. Moreover, depending on the molecular characteristics of polymeric and other fluids, the characteristics length scales that maximize slip and thus minimise resistance to flow should be optimized as such interrelationships are not known.