Surfactants in paint agent". Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or the interfacial tension between a liquid and a solid. In solutions this behavior is known as wetting, and it occurs as a result of surfactants adsorbing to the air/water interface. Soluble surfactants are also capable of forming micelles and other aggregate structures in solution, leading to a stabilizing effect in latex paints. Surfactants in paint are used to change many end properties of a dried paint, as well as to emulsify paints in their liquid state. Surfactants affect a wide array
Liquid as a linear medium, so that sound propagates without dissipation and without mode coupling. In reality, any liquid shows some dispersion: with increasing frequency, "K" crosses over from the low-frequency, liquid-like limit formula_6 to the high-frequency, solid-like limit formula_7. In normal liquids, most of this cross over takes place at frequencies between GHz and THz, sometimes called hypersound. At sub-GHz frequencies, a normal liquid cannot sustain shear waves: the zero-frequency limit of the shear modulus is formula_8. This is sometimes seen as the defining property of a liquid. However, just as the bulk modulus "K", the shear modulus "G" is