Wetting of different fluids. A shows a fluid with very high surface tension (and thus little wetting), while C shows a fluid with very low surface tension (more wetting action.) A has a high contact angle, and C has a small contact angle.

Wetting refers to the contact between a fluid and a surface, when the two are brought into contact. When a liquid has a high surface tension (strong internal bonds), it will form a droplet, whereas a liquid with low surface tension will spread out over a greater area (bonding to the surface). On the other hand, if a surface has a high surface energy (or surface tension), a drop will spread, or wet, the surface. If the surface has a low surface energy, a droplet will form. This phenomena is a result of the minimization of interfacial energy. If the surface is high energy, it will want to be covered with a liquid because this interface will lower its energy, and so on. Image File history File links Surfacetension. ... A subset of the phases of matter, fluids include liquids, gases, plasmas and, to some extent, plastic solids. ... In physics, surface tension is an effect within the surface layer of a liquid that causes the layer to behave as an elastic sheet. ... A chemical bond is the physical phenomenon of chemical substances being held together by attraction of atoms to each other through sharing, as well as exchanging, of electrons -or electrostatic forces. ... In physics, surface tension is an effect within the surface layer of a liquid that causes the layer to behave as an elastic sheet. ...

The primary measurement to determine wettability is a contact angle measurement. This measures the angle between the surface and the surface of a liquid droplet on the surface. For example, a droplet would have a high contact angle, but a liquid spread on the surface would have a small one. The contact angle and the surface energies of the materials involved are related by the equation: // In general Image from a video contact angle device. ...

where is the surface tension between two substances and s, v, and l correspond to the solid, vapor, and liquid substances in a contact angle experiment respectively.

A contact angle of 90° or greater generally characterizes a surface as not-wettable, and one less than 90° means that the surface is wettable. A wettable surface may also be termed hydrophilic and a non-wettable surface hydrophobic. Superhydrophobic surfaces have contact angles greater than 150°, showing almost no contact between the liquid drop and the surface. This is sometimes referred to as the "lotus-leaf effect". This characteristic of spreading out over a greater area is sometimes called 'wetting action' when discussing solders and soldering. The adjective hydrophilic describes something that likes water (from Greek hydros = water; philos = friend). ... In chemistry, hydrophobic or lipophilic species, or hydrophobes, tend to be electrically neutral and nonpolar, and thus prefer other neutral and nonpolar solvents or molecular environments. ... A solder is a fusible metal alloy (often of tin and lead, although lead-based solders were outlawed in many parts of the world in the 1980s), with a melting point or melting range below 450 °C (840 °F) and is melted to join metallic surfaces, especially in the fields... (De)soldering a contact from a wire. ...

Wetting is often an important factor in the bonding (adherence) of two materials. It is also the basis for capillary action, the ability of a narrow tube to draw a liquid, even against the force of gravity. Dew drops adhering to a spider web Water droplets adhering on a hibiscus petal Adhesion is the molecular attraction exerted between bodies in contact. ... Capillary action or capillarity (also known as capillary motion) is the ability of a narrow tube to draw a liquid upwards against the force of gravity. ... TUBE (チューブ; chūbu) is a Japanese popular music group. ...