Fabrication of core/sheath PCL/PEG–PNIPAAm fibers as thermosensitive release carriers by a new technique combining blend electrospinning and ultraviolet-induced graft polymerization

Abstract In this study, a new fabrication method combining blend electrospinning and ultraviolet-induced graft polymerization was developed to prepare core/sheath structure fibers. A series of thermally responsive fibers were prepared with medicated poly( e -caprolactone) (PCL) as the core and thermosensitive polyethylene glycol-poly( N -isopropylacrylamide) (PEG–PNIPAAm) as the shell via this method. Their morphology and chemical properties were studied by FESEM, TEM, and FT-IR. Analysis of the temperature-dependent release revealed that the addition of PEG into PNIPAAm shell would change the drug-release mechanism of the fibers. As more PEG chains were incorporated into PNIPAAm shell, PNIPAAm collapse temperature increased, and as a result, PEG–PNIPAAm shells prepared at feed polymer ratios of 5:5 and 4:6 (w/w) exhibited thermosensitive characteristic in the temperature range of 37–40 °C.