Contact Angle Measurement

In Jikan we provide you static and dynamic contact angle measurements as a service.

Understanding Contact Angle:

The formed angle between liquid-solid and gas-liquid lines, starting from inside of the liquid, is called contact angle.

Defining wettability, self-cleaning, surface free energy, hydrophobicity, and hydrophilicity are the main applications of using contact angle as a surface property. A surfacce with a water contact angle of less than 90 degrees is called a hydrophilic surface, but when its higher than 90 its called hydrophbic. In certain conditions water contact angle may go higher than 150 degrees and it's called superhydrophobic. Also when the contact angle is less than 10 degrees it's called a superhydrophilic surface.

Surface Coatings With Desired Wettability From Superhydrophobic to Superhydrophilic Coatings Are available In Jikan Services Section.

Static Contact Angle:

In this test a determined volume of a fluid in shape of a droplet is injected on the sample's surface, then an accurate camera takes images of the droplet on the surface and sends it to a computer. The computer processes the image and calculates the contact angles of the surface.

Dynamic Contact Angles:

Measuring static contact angle is not sufficient to determine surface wettability. Static contact angle is an unspecified angle between advancing and receding contact angles, that are the maximum and minimum of the all possible contact angles on a certain surface. The difference of these two, shows the contact angle hysteresis. These dynamic angles are unique for a surface and determine surface wettability in a suitable way.

In order to measure the dynamic contact angles, a specified amount of fluid, is injected to the droplet on the surface with a specified rate making droplet bigger and then it sucked out making droplet smaller. The measured contact angles during these steps are called advancing and receding contact angels respectively.

Sessile Drop Method:

Sessile drop method is the most popular and applicable method of measuring contact angles directly. It needs only a little bit of the liquid, and it's suitable for very small samples. The method consists of leaving a droplet on the surface, making images and processing the image in order to measure the contact angles.

Jikan CAG-10 and CAG-20 contact angle and surface tension goniometers do all this tasks according to international standards properly, and are also available for service.