How adhesives work?
To better understand how or why glue sticks to a surface, it is better to understand the mechanisms of adhesion. There are four known methods for attaching adhesives and tapes to surfaces:
- Chemical adhesion mechanism
- Mechanical locking mechanism
- Release mechanism
- Electrostatic adhesion mechanism
To better understand how or why glue sticks to a surface, it is better to understand the mechanisms of adhesion. There are four known methods for attaching adhesives and tapes to surfaces:
- Chemical adhesion mechanism
- Mechanical locking mechanism
- Release mechanism
- Electrostatic adhesion mechanism
Mechanical locking mechanism occurs when, during the bonding process, the adhesive penetrates the pores of the subsurface. Locking creates a physical barrier to crack propagation at the joint. It also increases the surface area, increasing the connection point between the adhesive and the underlying surface. Liquid adhesives flow to the substrate when they are dry and consistent. Adhesive bonds slowly expand and increase in strength over time.
Diffusion mechanism occurs when the polymer adhesive is able to penetrate and spread into the polymer substrate. The point of attachment of the adhesive polymer chains engages and integrates with the infrastructure. This mechanism is common in the assembly of materials with low surface energy such as polypropylene.
The mechanism of electrostatic adhesion occurs when an adhesive surface is attracted to an oppositely charged substrate, such as adhesive tapes. This phenomenon is often observed when trying to glue a box or gift package.