Polyphosphazenes fibers

Both types are hydrophobic materials that, depending on the side group arrangements, can exist as elastomers or as microcrystalline fiber- or film-forming materials. Preliminary studies have suggested that these two classes of polyphosphazenes are inert and biocompatible in subcutaneous tissue implantation experiments. 

The molecular architecture of a polyphosphazene has a profound influence on properties. For example, linear and tri-star trifluoroethoxy-substituted polymers with the same molecular weight (1.2 x 104 or higher) have strikingly different properties.138 The linear polymers are white, fibrous materials that readily form films and fibers, whereas the tri-arm star polymers are viscous gums. One is crystalline and the other is amorphous. Cyclolinear polymers are usually soluble and flexible. Cyclomatrix polymers are insoluble and rigid. Linear polymers can be crystalline, but graft or comb polymers are usually amorphous. 

M.S. Peach, et al.. Design and optimization of polyphosphazene functionalized fiber matrices for soft tissue regeneration, J. Biomed. Nanotechnol. 8 (1) (2012) 107-124. 

M.S. Peach, et al., Polyphosphazene functionalized polyester fiber matrices for tendon tissue engineering in vitro evaluation with human mesenchymal stem cells, Biomed. Mater. 7 (4) (2012) 045016. 

Finally, many polyphosphazenes have been studied as tbin films, solvent-extruded fibers, and nanofibers by solvent casting, spin casting, solvent extrusion, and electrospinning methods (Figures 7.2 and 7.5). These techniques have proved useful for semi-crystalline fluoroalkojyphosphazene polymers and for arylojy-substituted derivatives. 

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