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If a solid polymer has a drop of liquid (water) and shows a negative value of wetting tension, what does this mean? Does this mean that the drop of liquid will bead up instead of spreading on the solid surface?

I am trying to understand the wetting dynamics of a polymer's surface, wetted with water. Wetting tension (delta F), being one of the wetting parameters shows a negative value and does increase to a positive value after certain surface treatment. But in pristine form, it shows a negative value of wetting tension.

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"Wetting tension" is a term I am not familiar with. The common way to describe the wettability of one substance by a liquid (say, water) is to measure its contact angle. If the contact angle is greater than 90 degrees, the liquid tends to "ball up" on the surface and we say the surface is poorly wetted by the liquid. If less than 90 degrees, the droplet tends to spread out into a flattish shape and we say the solid is well-wetted. If the contact angle is 90 degrees, the droplet of fluid will form itself into a hemisphere.

Many polymers are poorly wetted by water until they have been treated by an oxygen plasma which creates a near-monolayer of "plastic oxide" on the surface. The oxygens that populate the surface resemble the oxygens in a water molecule, and it is therefore easy for water to wet out and get friendly with an oxygenated surface.

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