chemistry/surface energy help

[iwantanewcomputer]

i'm applying a rubber adhesive to different polyethylene materials. both phobic.

based on surface energy (contact angle) measurements, how can i tell if the adhesive will stick better to one polyethylene sample or another?

for example, the adhesive contact angle is 88*, polyethylene 1 is 85*, polyethylene 2 is 75*. which will the adhesive stick better to?

 

[CycloWizard]

Originally posted by: iwantanewcomputer
i'm applying a rubber adhesive to different polyethylene materials. both phobic.

based on surface energy (contact angle) measurements, how can i tell if the adhesive will stick better to one polyethylene sample or another?

for example, the adhesive contact angle is 88*, polyethylene 1 is 85*, polyethylene 2 is 75*. which will the adhesive stick better to?

All of the contact angles are measured in a glass container or what? That said, the contact angle probably won't tell you anything about the final adhesive quality, depending on the type of adhesive. When you say 'rubber adhesive', does that mean it's an adhesive that forms a rubber, or that it's meant for bonding rubbers? I guess I don't think you have enough information to really decide which will be better.

 

[iwantanewcomputer]

it's a rubber based adhesive, i think that if the substrate has the same surface energy as the adhesive, the will stick better than if they have different surface energies...googling this subject is just confusing

 

[CycloWizard]

Originally posted by: iwantanewcomputer
it's a rubber based adhesive, i think that if the substrate has the same surface energy as the adhesive, the will stick better than if they have different surface energies...googling this subject is just confusing

Well, the answer is,as with any good engineering question, it depends. If the adhesive reacts with the substrate, then the surface energies are not necessarily important, as the final state will be independent of the surface energy. Alternatively, if it works not by reacting but by forming non-covalent bonds with the substrate, the surface energy is very important. In this case, I speculate that similar surface energies will bond better. I have to admit that I'm not that familiar with surface energy phenomena, so it could be that the larger the surface energy gradient (i.e. larger difference between adhesive and substrate) could result in a better bond. There is someone in my department who would definitely know the answer, but he's AWOL this week. I'll see if I can get it out of him.