The method for measurement of contact angle meter: Why ADSA-RealDrop is the best.

Maybe you bought a goniometer but not contact angle meter!

Young-Laplace Equation fitting       based on Select Plane method  is Basic requirements

√ADSA－P                            is  Standard requirements

√ADSA-RealDrop  can Calculate left & right contact angle separately.                    is   Advanced requirements

From the definition of the contact angle, the contact angle is a Physical Chemistry property index formed by the interaction of surface tension between liquid/gas, surface free energy of solid, interfacial tension between solid-liquid  and gravity of liquid. Typically, contact angles are used to characterize the properties of solid materials, as well as direct evaluation indicators for the adhesion between liquid and solids. In order to be compared by each other, the value of contact angle of solid surface is usually refer to water droplet contact angle (using secondary distilled water with surface tension value 72.8 mN/m (at 20℃) ).

So the contact angle value is not a simple metric obtained from a geometric protractor using circle, ellipse or tangent (Polynomial) curve, but a very complex physicochemical index that combines the effects of surface tension, interfacial tension, gravity, etc.. This is the essential difference between them.

The water drop contact angle meter must be a test instrument for characterizing the Physical Chemistry properties of the solid surface under the condition that the surface tension value of the water is measured to ensure the consistency of the test probe water.