Surface modification of silicone elastomer using perfluorinated ether

Abstract

The surface properties of a poly(dimethylsiloxane) elastomer have been modified by reacting an allyl amide functional perfluorinated ether (PFE) to the siloxane network by a hydrosilation reaction. Examination of the surface by contact angle and X-ray photoelectron spectroscopy revealed that the perfluorinated ether migrates to the surface of the polymer, thus reducing its surface energy from 22 to about 8 mJ/m2 without affecting its bulk material properties. The resultant surface however exhibits higher contact angle hysteresis than that seen with the PFE-free elastomer. These results indicate that the higher energy amide functionalities of the perfluorinated ether are available for interfacial interaction, even though they are buried below the PFE layer. This study demonstrates that a high-energy group can be pulled to the free surface of a polymer by the driving forces of the lower energy groups segregating to the surface. The high-energy groups are available for further chemical interactions when the surface reconstructs in contact with a high-energy environment.