Adhesion is the tendency for different particles or surfaces to stick together. There are various sorts of forces that generate adhesion and cohesion. Chemical adhesion, diffraction adhesion, and diffusive adhesion are the three types of intermolecular forces accountable for the function of various types of stickers and sticky tape. There are other emergent mechanical effects in extra to the aggregate magnitudes of these intermolecular forces.
Chemical Adhesion: At the joint, two materials may combine to form a composite. The strong joints form where the atoms of the two substances share or swap electrons.
The process of hydrogen bonding occurs when a hydrogen atom in one molecule attracts an atom of nitrogen, oxygen, or fluorine in another molecule, resulting in a weaker link.
When the surface atoms of two different surfaces form ionic, covalent, or hydrogen bonds, chemical adhesion happens. In this way, the engineering idea underpinning chemical adhesion is quite simple and clear. If surface molecules can link, then a network of these bonds will bind the surfaces collectively. It’s worth noting that these ionic and covalent forces are only active over extremely short distances — less than a nanometer.
Mechanisms: There is no single theory that encompasses adhesion, and certain mechanisms are unique to specific material conditions. Five adhesion mechanisms propose to describe why one material attaches to another.
Strength: The adhesion strength between two materials is determined by which of the above mechanisms occurs between the two materials. Although, the surface area over which the two materials come into contact. Materials that come into contact with one another when we have a bigger contact area than those that do not. Wetting determines by the surface energy of materials.
The stickiness is associated with sliding one thing on a substrate, such as a drop on a surface called lateral adhesion. Friction is the term for lateral adhesion between 2 solid objects, whether or not there is a liquid between them. However, lateral adhesion between a fall and a surface behaves differently tribologically than friction between solids, and the naturally sticky contact between a flat surface and a liquid drop creates lateral adhesion a distinct field in this situation.