Goniometer (Rame-Hart A-100) - Operating Procedure
To measure the contact angle of water on a surface, perform the following procedure.
- Note that the image through the scope is inverted upside-down.
- You will also see a reflection of the water droplet on your polished substrates, as illustrated here:
Alternate Measurement Technique - Tilt Angle
An alternate, "quick and dirty" method for comparing hydrophobicity between surfaces is to drop an identical amount of water on each sample's surface, and tilt the sample until the drop rolls off - the tilt angle required can be compared. This technique is much more "noisy" than the goniometer, but can be done without highly specialized equipment.