Hydrogen bonding surface tension

The Polar and Hydrogen-Bonding Surface Tension Components of Water for... 

Estimate the dispersion, polar and hydrogen bonding surface tension contributions (y, y, y ) of Teflon. You can assume that the polar and hydrogen bonding (surface tension) contributions of Teflon (y, y ) are equal. 

Using this value and again Equation 6.2.2, this time for propylene carbonate/Teflon, we can estimate the polar and hydrogen bonding surface tension contributions of Teflon, assuming that they are equal to each other ... 

We observe that the total surface tension of the (solid) Teflon as calculated by adding the three surface tension contribution is 19.64 mN m , which is rather close to the value of the critical smface tension (as could be expected - the critical surface tension is a measure of the solid surface tension). Moreover, we observe that the polar and hydrogen bonding surface tension contributions are both extremely small compared to the dispersion contribution, which is by far the dominant one for Teflon. 

From the above equation, we calculate the /-value, which best fits the data. This is / = 1.9228. Thus, the dispersion, polar and hydrogen bonding surface tensions of PS are calculated to be 26.28,4.65 and 2.067 mN m , respectively. The highest contribution comes from the dispersion forces, as could be expected (PS is a hydrocarbon polymer). 

Then we find the dispersion, polar and hydrogen bonding surface tension of formamide using the Hansen... 

Water forms hydrogen-bonded clusters with itself and with other proton donors or acceptors. Hydrogen bonds account for the surface tension, viscosity, liquid state at room temperature, and solvent power of water. 

KEY TERMS hydrogen bonding intermolecular forces surface tension... 

In the body of a liquid, intermolecular forces pull the molecules in all directions. At the surface of the liquid, the molecules pull down into the body of the liquid and from the sides. There are no molecules above the surface to pull in that direction. The effect of this unequal attraction is that the liquid tries to minimize its surface area. The minimum surface area for a given quantity of matter is a sphere. In a large pool of liquid, where sphere formation is not possible, the surface behaves as if it had a thin stretched elastic membrane or skin over it. The surface tension is the resistance of a liquid to an increase in its surface area. It requires force to break the attractive forces at the surface. The greater the intermolecular force, the greater the surface tension. Polar liquids, especially those that utilize hydrogen bonding, have a much higher surface tension than nonpolar liquids. 

---