Hydrophobic and superhydrophobic surfaces from polyphosphazenes

Hydrophobic polymers play a crucial role in many biomedical and commercial applications. Hydrophobic polyphosphazenes offer opportunities for the tuning of surface properties that are not found for many conventional hydrophobic materials. Thus, changes in the side groups linked to the polyphosphazene skeleton allow the surface character to be changed from highly hydrophilic to hydrophobic. The hydrophobic side groups range from fluoroalkoxy groups to aryloxy and organosilicon units. Moreover, the polymer architectures can be varied from single-substituent species to mixed substituent polymers or to block or comb copolymer structures. Superhydrophobicity, with contact angles to water as high as 159°, has been achieved by electrospinning a fluoroalkoxy derivative to nanofiber mats.