Reconstruction of the interface of oxidatively functionalized polyethylene (PE-CO sub 2 H) and derivatives on heating.

Oxidation of low-density polyethylene film with aqueous chronic acid results in a material (PE-CO sub 2 H) having hydrophilic carboxylic acid and ketone groups in a thin oxidatively-functionalized interface. This interface is indefinitely stable at room temperature. On heating in vacuum, it rapidly becomes hydrophobic and similar to unfunctionalized polyethylene film. The progression of the contact angle with water from the initial value (55degrees) to the final value (103degress) follows kinetics that suggest that the polar functional groups disappear from the interface by diffusion.