Dynamic Relaxation and Glass Transformation of Electrospun Fibrous Membrane with Confined Chain Configuration: for Physical Aging and Shape Function Control and Delivery

The thermodynamic glass transformation processes of electrospun membranes are firstly introduced to study the dynamic relaxation nature of this not always in equilibrium transformation process. The relaxation modes of the electrospun membrane are slow but measurable in the vicinity of the Tg and even above the Tg due to the stretched chain in long distance. Based on the differential scanning calorimetry (DSC) experiments and the general principle of mode-coupling theory (MCT), the endothermic peak temperature and the relaxation enthalpy were used to analyze the relaxation process by capturing these instantaneous "arrested" structures. With different annealing time and annealing temperatures relative to DSC measured T for E-spun membrane with different molecular weight, the short and long wavelength relaxation modes could be identified. These results clearly show the dynamic nature of the glass transition in polymeric materials which can be explained by the general principle of MCT type of dynamic theory.