Bonded solid adsorption of adhesives as a main cause of theory, known as adsorption theories of bonding. Theory: major source of bonding is an intermolecular bonding system, namely, Vanderbilt and attraction of hydrogen bonds. When the distance between the adhesive and the adherend 10-5Å is reached, interface will have a mutual attraction between the molecules, the distance between molecules is further reduced to a maximum steady-state.
According to calculations, due to van der Waals forces, when two ideal Planar 10Å apart, and gravitational strength up to 10-1000MPa between them; when 3-4Å is distance, up to 100-1000MPa. That number far exceeds the best for structural adhesive strength can be achieved. Therefore, some people think that when two objects very well, namely adhesives on the bonding interface full wetting, calculated values assuming an ideal surface in close contact, and to ensure the interface layer of the destruction at the same time, there can be no assurance the forces between the molecules together.
The polarity of the adhesive is too high, sometimes seriously hampers the wet process and reduced adhesion. Intermolecular forces is to provide adhesion factors, but not the only factor. In special cases, other factors can also play a leading role.