Surface Dynamics of Hydrophilic Polymers

The interaction of water molecules with polymer molecules at the surface does not necessarily require contact with the condensed (liquid) phase. If the mobility of polymer segments increases with the sorbed water, a significant extent of surface configuration change could take place even with the change of relative humidity in 

A highly hydrophobic polymer such as Teflon PFA has weak x interaction with water. The y interaction is strong in liquid water but very weak in contact with water vapor. When the hydrophilicity of polymer increases the contribution of the x interaction increases, and the relative contribution of the y interaction changes according to the value of A(yg). 

---