Wicking Properties - Contact Angle in a Capillary

header

Home | About HLTH | About Porex | Support | Contact Us

Contact Angle in a Capillary

A capillary typically is defined as a tube having a very small inside diameter. Using the previous example as a starting point, a capillary is simply our liquid, solid, gas interface as described above rotated about an offset axis running parallel to the liquid-solid interface. Because of this, the principles involving contact angle and interfacial surface energies still apply.

Click here to view the Contact Angle in a Capillary animation.

The primary and most notable difference between the two examples concerns the creation of a contact angle that spans the entire capillary tube. When viewed in a two dimensional fashion, a meniscus is created from the liquid’s contact angle with the solid. As a result and in accordance with the summary of our earlier discussion involving the liquid droplet, we can use the contact angle (or meniscus shape) to determine the relative strengths of the interfacial surface energies.

If the interfacial surface energies are varied, the contact angle (meniscus shape) changes until equilibrium is reestablished. Note the changes that occur in the liquids contact angle (meniscus shape) when the liquid’s surface energy is first increased and then decreased. Then, note the changes that occur to the contact angle (meniscus shape) when the solids surface energy is first increased and then decreased. In both cases, the shape of the contact angle (meniscus shape) conforms to balance interfacial surface energies.

Wicking Properties

Pore Size Distribution - Capillary Flow
Water Flow vs Differential Pressure
Capillary Theory
Interfacial Surface Energy and Contact Angle
Capillary Force, Capillary Pressure & Capillary Head

Pore Size Distribution - Mercury Intrusion
Water Intrusion Pressure
Surface Energy Cohesive Forces
Contact Angle in a Capillary
Capillary Theory Conclusion

header