Researchers propose theoretical model to describe capillary force balance at contact line

April 16, 2020

Recently, a group led by Prof. WU Heng'an and Prof. WANG Fengchao from University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) in collaboration with Prof. Joel De Coninck from University of Mons provided a theoretical insight into capillary forces at the contact line and validated Young's equation based on a mechanical interpretation. The research results were published online in Physical Review Letters.

In 1805, the British scientist Thomas Young described the quantitative relationship between interfacial tension and contact angle when studying wetting and capillary phenomena. For more than 200 years, the Young's equation has become one of the most basic theories in the field of wetting. It describes the balance of three interface tensions parallel to the solid-liquid interface. However, researchers have disputed its interpretation as surface forces or surface energies and committed to prove its validity at the nanoscale.

Despite remarkable progress achieved in past years, puzzles and challenges still remain. First, the capillary force is not presented in the Young's equation. Additionally, the Young's equation cannot be verified directly in experiments. Compared with its thermodynamic derivation, there are more obstacles to put forward the mechanical interpretation of the equation.

To solve the problem, a theoretical model was proposed by the group from USTC to describe the capillary force at the contact line.

The researchers examined the capillary force balance on a liquid corner on the atomic scale and considered this problem with a liquid in coexistence with its vapor phase. The analysis was based on the decomposition of the solid-liquid and solid-vapor interface tensions into three terms, either of which has a clear physical meaning. The proposed model is verified by molecular dynamic simulations over a wide contact angle range. Differences in capillary forces are observed in evaporating droplets on homogeneous and decorated surfaces.

Following the same approach, they also verified Young's equation at the nanoscale from a view point of mechanical interpretation. Microscopic details regarding the mechanism of wetting and capillarity. These results provide new physical insight into the capillary force balance at the contact line.

This study not only provides new insights for the profound understanding of many phenomena of interface wetting, but also has important scientific significance in the application fields of micro-nano fluidic chip design and the improvement of low-permeability reservoirs recovery.
-end-


University of Science and Technology of China

Related Balance Articles from Brightsurf:

It's all about the right balance
Collaborative work of research groups at the University of W├╝rzburg and the TU Dresden has provided important new insights for cancer research.

Immune system -- Knocked off balance
Instead of protecting us, the immune system can sometimes go awry, as in the case of autoimmune diseases and allergies.

Finding balance between green energy storage, harvesting
Generating power through wind or solar energy is dependent on the abundance of the right weather conditions, making finding the optimal strategy for storage crucial to the future of sustainable energy usage.

Quantum jump tipping the balance
Measuring tiny differences in mass between different quantum states provides new insights into heavy atoms.

Examining associations between hearing loss, balance
About 3,800 adults 40 and older in South Korea participating in a national health survey were included in this analysis that examined associations between hearing loss and a test of their ability to retain balance.

Pancreatic cancer blocked by disrupting cellular pH balance
Scientists at Sanford Burnham Prebys have found a new way to kill pancreatic cancer cells by disrupting their pH equilibrium.

Stop or go: The cell maintains its fine motility balance with the help of tropomodulin
Tropomodulin maintains the fine balance between the protein machineries responsible for cell movement and morphogenesis.

Need to balance guides development of limb-body coordination
The need to feel balanced drives the development of coordination between body and limbs as zebrafish larvae learn to swim, a new study finds.

Scientists weigh the balance of matter in galaxy clusters
A method of weighing the quantities of matter in galaxy clusters - the largest objects in our universe - has shown a balance between the amounts of hot gas, stars and other materials.

A matter of fine balance
How does the brain's circuitry adjust itself to make sense of the world despite the hugely different signals it receives?

Read More: Balance News and Balance Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.