Related Experiment Video
Updated: Jun 8, 2026
08:58
Atomic Force Microscopy Cantilever-Based Nanoindentation: Mechanical Property Measurements at the Nanoscale in Air and Fluid
Published on: December 2, 2022
A unified force-energy adhesion model for wettability on real solid surfaces.
1Department of Mechanical Engineering, Kunsan National University, Gunsan, South Korea.
Journal of Colloid and Interface Science
|June 6, 2026
Summary
Real solid surface wettability is better described by a new adhesion coefficient, which quantifies deviations from ideal wetting. This parameter, derived from force and energy balances, provides a universal scaling for diverse surfaces and liquids.
Area of Science:
- Surface Science
- Physical Chemistry
- Materials Science
Background:
- Wettability of real surfaces is complex, influenced by roughness and chemical variations.
- The apparent contact angle alone is insufficient to describe wetting behavior.
- Existing models struggle to capture the full picture of liquid-solid interactions.
Purpose of the Study:
- To develop a unified theoretical framework for liquid droplet wetting on rigid solid surfaces.
- To quantify the deviation from ideal Young's surface using a single, surface-specific parameter.
- To link force-based and energetic descriptions of wetting phenomena.
Main Methods:
- Coupling mass conservation with force and energy balances.
- Defining an adhesion coefficient based on wetting potential ratios.
- Comparing theoretical predictions with extensive experimental data for various surfaces and liquids.
Main Results:
- Developed a unified theoretical framework for wetting, incorporating an adhesion coefficient.
- The adhesion coefficient effectively describes surface properties, leading to universal scaling.
- Obtained explicit expressions for nondimensional work of adhesion and a normalized Zisman-type relationship.
Conclusions:
- The adhesion coefficient provides a compact, dimensionless description of wettability on real surfaces.
- A critical contact angle, dependent on the adhesion coefficient, distinguishes hydrophilic and hydrophobic regimes.
- This approach extends classical contact-angle interpretations for a more comprehensive understanding of wettability.
Related Concept Videos
02:57Surface Tension, Capillary Action, and Viscosity
Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
01:24Surface Tension
Surface tension is defined as the force per unit length (γ) acting along the surface of a liquid. It arises due to strong intermolecular forces of attraction. A molecule located inside the bulk of the liquid is surrounded by other molecules and experiences equal forces in all directions. However, a molecule at the surface experiences unbalanced forces because there are more neighboring molecules below than above. This creates a net inward force that pulls surface molecules toward the interior,...
01:14Adhesion
Adhesion occurs when one type of molecule is attracted to a different molecule. Water exhibits adhesive properties in the presence of polar surfaces, such as glass or cellulose in plants. For instance, when water is poured into a glass, the positively charged hydrogen molecules of water are more attracted to the negatively charged oxygen molecules in the silica than to the oxygen in neighboring water molecules.
Capillary action is a result of water’s adhesive tendencies. When a narrow glass...
Capillary action is a result of water’s adhesive tendencies. When a narrow glass...
01:16Surface Tension and Surface Energy
When a paint brush is immersed in water, the bristles wave freely inside the water. When it is taken out, the bristles stick together. The reason behind this effect is surface tension.
Consider a beaker filled with liquid. The bulk molecules in the liquid experience equal attractive forces on all sides with the surrounding molecules. However, the surface molecules experience a net attractive force downward due to the bulk molecules. The surface of the liquid behaves like a stretched membrane,...
Consider a beaker filled with liquid. The bulk molecules in the liquid experience equal attractive forces on all sides with the surrounding molecules. However, the surface molecules experience a net attractive force downward due to the bulk molecules. The surface of the liquid behaves like a stretched membrane,...
01:22Surface Tension of Fluid
Surface tension is a fundamental property of fluids, occurring at the boundary between a liquid and a gas or between two immiscible liquids. This phenomenon arises from the cohesive forces between molecules at the fluid's surface, creating an effect similar to a stretched elastic membrane. Inside each fluid, molecules are equally attracted in all directions by neighboring molecules, but surface molecules experience a net inward force, resulting in surface tension.
Surface tension varies with...
Surface tension varies with...
01:07Cohesion
Cohesion is the attraction between molecules of the same type, such as water molecules. Water molecules have an overall neutral charge but are polar molecule. An oxygen atom in one water molecule has a partial negative charge that can bind to a hydrogen atom with a partial positive charge in a second water molecule, forming a hydrogen bond. Each water molecule can form up to four hydrogen bonds with other water molecules. Hydrogen bonds are responsible for water's cohesive nature.
On a surface,...
On a surface,...