Methods of increasing hydrophobicity of polyurethane materials: important applications of coatings with low surface free energy

The synthesis of polyurethane coatings by polyaddition in bulk using polyesterols and polyetherols with variable polarity was successfully carried out. IR and NMR spectra confirmed the structure of obtained polyurethanes and the incorporation of a polydimethylsiloxane(PDMS) modifier into the polyurethane structure. The differential scanning calorimetry and IR spectroscopy were employed for the microstructural assessment of the obtained materials. It was noted that crucial effect on free surface energy of the coatings has polyol structure as well as ratio of hard to soft segments. The contact angle measurements indicated that with increasing content of the polysiloxane in the flexible PTMO segments, the hydrophobicity significantly increased. It was demonstrated that hydrophobicity and mechanical strength, which are important for applications as biomaterials, are adversative in significant extent. The resulting coatings were characterized in terms of the heat resistance and changes during incubation in a Baxter saline solution.