If considerable surface tension differences must be equalized, polysiloxanes can be used. Depending on their chemical structure, they can considerably reduce the surface tension of the liquid coating. They can therefore preferentially be used to improve the substrate wetting and as anti-cratering additives. Given sufficient incompatibility with the coating system, polysiloxanes can also have a defoaming effect. Moreover, silicone additives also improve the surface slip of the cured coating film, and can therefore help improve scratch and block resistance.
Polyacrylates can only equalize small surface tension differences and either do not reduce or only slightly reduce the surface tension of the liquid coating.
They are predominantly used to improve leveling. However, with sufficient incompatibility, these products can also exhibit defoaming properties. In addition, there is the group of low-molecular weight surfactants that are likewise surface active, due to their typical amphiphilic structure (polar/non-polar), and can be used to reduce surface tension.