Adhesion force and surface tension of glue

Information about the adhesion force and the surface cushion of the ice will help you to choose a better material.

Two forces are involved in the bonding mechanism of adhesives, which are van der Waals forces and chemical bonds. Van der Waals forces are the basis of most adhesion processes. These attractive forces act between the adhesive and the desired object. Chemical bonds create the strongest type of adhesion. This type of bonding occurs when the object on which the adhesive is applied has chemical groups that react with the adhesive. Some chemical groups are very effective in generating van der Waals forces, and if present in the adhesive or object in question, they create a good bond. Nitrile, hydroxyl, carboxyl and Omid groups can be mentioned among these groups.

In order to create adhesion between the adhesive and the object, it is necessary that the materials come into contact with each other. In this case, the surface tension controls the contact of the adhesive with the solid object. All materials have surface forces, which are known as surface tension in liquids and surface energy in solids. Surface tension is what causes drops in a liquid.

If the surface energy in the solid is greater than the surface tension of the liquid, the glue drop will spread and spread on the surface of the solid object, causing wetting and better adhesion; Therefore, by increasing the surface energy of the solid or by decreasing the surface tension of the liquid, the wetting of the solid surface can be improved.

Critical surface tension Critical surface tension is the surface tension required to wet a solid surface. The critical surface tension of clean metals and metal oxides is higher than the surface tension of aluminum and water, and solid organic resins have a lower critical surface tension than water. It is difficult to form a connection with polyethylene, CFCs and silicones due to their lower critical surface tension than the critical surface tension of most adhesives.