Here we see a surface that is patterned with hydrophilic circular areas that are surrounded by hydrophobic areas. Water condenses on and is confined to the hydrophilic areas, form water droplets that grow to a point where the droplets become so large, they touch each other. The use of such patterned surfaces is used to make microfluidic devices where the flow of very small amounts of liquids is guided across a surface and mixed with other fluids. Very small drug delivery devices and sensors are built on this principle. Learn more.
Photo credit: McCarthy Research Group, courtesy of Visual Image Library