Sessile Drop Method

Optical contact angle measurement to determine the wetting behaviour of solids

Task
Determination of the static and dynamic contact angle and of the surface free energy of solids

Test results: interface-specific parameters and measuring ranges of typical instrument systems

• Measurement of the static contact angle of sessile drops of liquid on a surface as a function of time or temperature
• Measurement of the dynamic contact angle as a function of the dosing rate , as advancing angle or as receding angle
• Measurement of the difference between advancing angle and receding angle (contact angle hysteresis) by metered addition or removal of liquid
• Measurement of the contact angle or until the rolling off of the drop on a plate inclined with the angle (Tilting Plate method)
• Calculation of the critical surface tension and of the surface free energy : determination of the dispersion as well as the non-dispersion parts (e.g. polar parts , acid/base parts , hydrogen bonding parts ) from contact angle measurements with various test liquids
• Typical measuring ranges : 0 ... 180�/0,1 mN/m ... 1000 mN/m