Optical Tensiometry

Optical tensiometry is a versatile technique used to characterize material surface properties and interfacial interactions between gas, liquid and solid phases. Optical tensiometers are used in R&D and quality control in a variety of industries, including biomaterials, chemicals, pharmaceuticals, electronics, foods, energy, environment, paper and packaging.

Optical tensiometers are primarily developed for the measurement of contact angles and surface free energy. They are also capable of determining surface tension, interfacial tension, 3D surface roughness and interfacial rheology.


Measuring surface tension, interfacial tension, contact angles or surface roughness provides information on material properties such as wettability, absorption, surface free energy, adsorption, spreading, cleanliness, surface heterogeneity and interfacial rheology Information on these properties is pivotal when studying and developing engineered surfaces and technical liquids, and when controlling solid surface and liquid quality.

Optical tensiometers capture drop images and automatically analyze the drop shape as a function of time. The drop shape is function of surface tension of liquid, gravity and the density difference between sample liquid and the surrounding medium. On a solid, the liquid forms a drop with a contact angle that also depends on the solid’s surface free energy. The captured image is analyzed with a drop profile fitting method to determine contact angle and surface tension.


Standard Test Methods
TM D733‑08Surface wettability of coatings, substrates, pigments by advancing contact angle measurement.
ASTM D7490‑08Surface tension of solid coatings, substrates and pigments using contact angle measurements.
ASTM D5946‑09Corona treated polymer films using water contact angle measurements.
ASTM C813‑90Hydrophobic contamination on glass by contact angle measurement.
ASTM G205‑10Determining corrosivity of crude oil.
ISO 15989:2004Plastics — Film and sheeting. Water-contact angle of corona-treated films.
ISO 27448:2009Fine ceramics. Self-cleaning performance of semiconducting photocatalytic materials.
T 458 cm‑04Surface wettability of paper (angle of contact method).
T 558 om-10Surface wettability and absorbency of sheeted materials like paper using an automated contact angle tester.

For information about the standard test methods above, see: