Dynamic contact angle measurements on various fabric surfaces using a simple optical vision system

Abstract

A contact angle measuring device was developed for undergraduate Physics laboratory experiments. The new device was tested on determining the wettability of waterproof fabrics. Intel^® Play^TM QX3^TM Computer Microscope was used in determining the changes in time of the contact angles of different waterproof fabrics washed in different conditions. At contact angles between 80 to 90 degrees, the untreated samples changed its wettability from being hydrophobic to being hydrophilic. For washed samples it was determined that the change in wettability occurred at contact angles between 40 to 70 degrees. The rate of recession of the contact angle of the water droplet was related to the rate of absorbance of the waterproof fabric. It was found that high temperature of water used for washing increases the rate of recession. Measurements of the contact angle in time were able to show the dynamic behavior of the water droplet on the fabric surface.