Frequently Asked Questions
Surface energy values usually have the units of mJ/m 2. Some sources quote the critical surface tension in units of mN/m, which is equivalent to surface energy. The surface energy values of some typical materials are shown in the two tables. The first table shows values for low and high surface energy solid materials, whilst the second table shows values for the liquids used in contact angle measurements that are used to determine surface energies.
There are various methods for obtaining surface energy values and there can be some variation in the values determined, dependent on the method used. This variation reflects the genuine difficulties that exist in performing these types of measurement, and this topic is still an area of active research as greater levels of understanding are sought.
Table of surface energy values of solid materials
|Material type ||Surface energy (mJ/m 2), γS (Experimental, estimate * or theoretical † .) |
| Low energy surfaces - plastics, rubber and composites |
Polytetrafluoroetylene - PTFE
Poly(vinylidene fluoride) - PVF
Polyethylene - PE
Polypropylene - PP
Poly(methylmethacrylate) - PMMA
Polystyrene - PS
Polyamide - PA, Nylon-6,6
Poly(vinylchloride) - PVC
Epoxy - typical rubber toughened
Epoxy - typical amine-cured
Carbon fibre reinforced plastic (CFRP) abraded
| High energy surfaces - metals, oxides and ceramics |
|Aluminium oxide (Al 2O 3) - anodised |
Aluminium oxide (Al 2O 3) - sapphire
Berylium oxide (BeO)
Iron oxide (Fe 2O 3)
Silicon dioxide - silica
1107 ( † )
1360 ( † )
1250 ( † )
1357 ( † )
442 ( † )
319 ( † )
1770 ( † )
890 ( † )
Source of information: 'Adhesion & Adhesives - Science & Technology', A J Kinloch, Chapman & Hall, London, 1987.
Table of surface energy values of liquids used for surface energy measurements
|Liquid ||Surface energy (mJ/m 2) γLV |
Source of information: 'Adhesion & Adhesives - Science & Technology', A J Kinloch, Chapman & Hall, London, 1987
FAQ: What treatments exist for altering the surface energy of a material?
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