Surface modification of a polycarbonate-urethane using a vitamin-E-derivatized fluoroalkyl surface modifier.

Fluorinated surface-modifying macromolecules (SMMs) have been previously reported on and shown to limit the hydrolytic degradation of polyurethanes. The SMM molecules achieve this effect by allowing for the selective migration of terminal fluorinated groups to the polymer's surface, which may then shield more hydrolytically-sensitive groups in the base polyurethane backbone. A further extension of the SMM concept would be to utilize the migration of the fluorine tails to simultaneously deliver biologically active moieties to the surface. This study explored the synthesis and characterization of a vitamin-E (natural anti-oxidant) coupled surface modifier, as a model for the bioactive SMM concept. The SMM was synthesized using lysine diisocyanate (LDI), polycarbonate diol (PCN), and a fluoroalcohol. By derivatizing the LDI pendant ester, vitamin E was coupled to the SMM. The vitamin-E SMM was physically characterized using gel-permeation chromatography (GPC) and its anti-oxidant activity was assessed in the presence of 0.1 mM NaOCl. Polymer degradation experiments were carried out using 10 mM NaOCl incubation solutions, and the relative material breakdown was assessed using GPC and scanning electron microscopy (SEM). The results indicate that while the fluoro-component reduced damage of the PU, the bioactive component achieved a further deactivating effect. A similar action may also be effective against superoxide anions generated by human macrophages.