12 May 2014 | 10:10am
By Dr Daryl Williams

Ever since our company invented a Surface Energy Analyser 2 years ago, I have been often asked the question what is surface energy? Why should I measure it and what will I learn if I do?

Well really it is quite easy, it simply a way of quantitatively measuring how “sticky” a material surface is from a chemical perspective. That is, to be more precise, it is a measure of how strongly particles adhere together when you are processing powders for example, or how strongly a liquid will bind to a surface. In a way it is cousin to the surface area which is one of the most commonly measured properties of powders. For a powder for example, surface area is a physical concept- how much area is present whereas surface energy a chemical concept- how chemically active is that surface area.

Indeed measuring the surface energy of powders, fibres or films is crucial to understanding how they interact with other liquids and solids. In the real world surface energy is critical to understanding problems such as:

Will my ink wet the surface I am printing onto?
Will my powder disperse into the liquids systems I am working with?
Can the powder I have flow easily out of a hopper or in a processing line?
Have I coated by fibres completely with my additive?
When I mill or grind solids to make smaller particles, how have the surface properties of the materials changed?
If I wet granulate a powder, will the liquid wet the particles completely?
If I modify a surface chemically, was that reaction complete?
Is my material more hydrophobic or hydrophilic now?

If you are still wondering about the relevance of surface energy to your challenges, you may contact Dr Daryl Williams and ask specifically about your specific interest by sending email to [email protected].

About the author:
Dr Daryl Williams is the Director of the Discovery Space and Reader in Particle Science at the Chemical Engineering Department at Imperial College and founder of Surface Measurement Systems Ltd. He invented the scientific technique Dynamic Vapour Sorption (DVS).

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