Grafting of poly(ε-caprolactone) on electrospun gelatin nanofiber through surface-initiated ring-opening polymerization

Gelatin–polycaprolactone hybrid materials are being used in medicinal applications such as drug delivery, tissue engineering applications nowadays. In this study, gelatin–polycaprolactone graft copolymer was synthesized through ring-opening polymerization process instead of conventional grafting methods using potentially cytotoxic crosslinkers, or applying plasma, aminolysis reactions. Gelatin nanofiber (GNF) was produced by electrospinning process before immobilization of poly(ε-caprolactone). Ring-opening polymerization of ε-caprolactone was successfully initiated on the surface of GNF using tin(IV) isopropoxide and gelatin (primary amine functional groups) as an initiator and a coinitiator, respectively. The growing of polymer chains on GNF was indicated by both scanning electron microscope and energy-dispersive X-ray spectroscopy. Chemical structure was characterized through infrared spectrum, thermal behaviors and the material composition was analyzed with thermogravimetric analysis, wettability and hydrophilicity were determined by water contact angle measurements.