Study On The Synthesis Of Polyphosphazenes And Their Surfaces

In the present thesis, poly(bisphenoxy)phosphazene, poly[bis(p-methylphenoxy)] -phosphazene and poly[bis(2,2,2-trifluoroethoxy)]phosphazene were synthesized respectively by the reactions of sodium salts with linear poly(dichlorophosphazene), which was obtained from hexachlorocyclotriphosphazene by thermal initiated ring-open polymerization. The polymers were characterized with FT-IR, ~1H NMR, GPC, DSC and TGA.The formation of carboxylic acid units at the surface of poly[bis(p-methylphenoxy)]phosphazene was carried out with the use of potassium permanganate. Dense films were prepared to evaluate the effects of pendant groups on the wettability, platelets adhesion, adsorption behavior to bovine serum albumin (BSA) and cell adhesion, respectively. The results demonstrated that the pendant groups with low surface energy can endow the polyphosphazenes with excellent water repellency, so the poly[bis(2,2,2-trifluoroethoxy)]phosphazene surface exhibits the best hydrophobicity (104±2° water contact angle). BSA adsorption, platelets and cell adhesion of polyphosphazenes were studied using different characterization techniques (Vis-UV spectroscopic ellipsometry and Scanning electron microscopy) to examine the biocompatibility of polyphosphazene surfaces. The results conformed that the pendant group had a great effect on the biomedical properties of polyphosphazenes.Nanofibers or microspheres of polyphosphazenes were fabricated through electrospinning/electrospraying from solutions in the proper process parameter, and the wettability of these surfaces were studied with water contact angle (WCA). It revealed that the structure of pendant groups and surface geometrical microstructures had great effects on the hrdrophobic properties of polyphosphazene surfaces. Further, the electrospun nanofiber mats supported the adhesion of platelets as well as promoted the adhesion and proliferation of lens epithelial cell (LEC).