Unexpected wettability

6 Plot of COS0 versus w/d for SU8 square pillar array surfaces (Reproduced with permission from [17], Copyright 2010 American Chemical Society) 

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The higher aqueous suspension dosage Is unexpected since its concentration is only 43% while that of the wettable powder is 50%. 

Amott method, to be preferentially oil-wet, RDI= —0.82. Laboratory work was undertaken to determine the feasibility of injecting alkaline solutions to improve oil recovery. These experiments were designed to produce surfactants in-situ. The surfactants would both lower the interfacial tension and react with the reservoir rock surface to modify the wettability of the porous media. The experimental work considered the injection of seawater and sodium hydroxide mixtures into cores. The experimental results show that the oil recovery was higher than 50% when the alkaline solution was injected. The conclusion was that surfactant produced by alkaline injection altered the rock wettability from oil-wet to intermediate-wet, increasing oU recovery. One precaution with alkaline flooding is that the range of reactions and the change in pH can cause unexpected variation in oil recovery if the reservoir and fluids are not well characterized. 

Superhydrophobic surfaces have a number of potential applications such as dust-free and self-cleaning surfaces for solar cells and satellite dishes, corrosion-resistant surfaces for heat transfer devices, transparent and antireflective surfaces, anti-freezing and anti-snow surfaces [1], The fact that Uquid in contact with such surface slides with low friction su ests applications such as the fabrication of microfluidics and medical devices. The non-wettable character has been claimed in biomedical applications ranging from blood vessel replacement to wound management [6], Other unexpected applications will emerge as the technology of making non-wettable surfaces matures. 

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