Researchers with Aalto University (Espoo, Finland) developed a measurement technique called scanning droplet adhesion microscopy (SDAM), which is extremely sensitive and 1,000 times more precise than current state-of-the-art wetting characterization methods.
The researchers use a droplet of water to measure the water-repellent properties of a surface by recording the nanonewton force when the droplet touches the surface and when it separates from the surface.
By measuring this force at many locations with micrometer spacing between the measurement points, they can construct a two-dimensional image of the surface’s repellency, called a wetting map.
Defects in self-cleaning, anti-icing, anti-fogging, anticorrosion, and anti-biofouling coatings can affect the functional integrity of the whole surface. SDAM detects microscopic defects of a surface, which would allow coating manufacturers to control the quality of materials.
This new concept for hydrophobic surface characterization opens a window for investigating structure-property relationships in surface wetting.
Source: Aalto University, www.aalto.fi.
