Study On The Process Of PLA Emulsion Electrospinning

Emulsion electrospinning can produce bicomponent nanofiber with compositestructure.Compared with co-axial electrospinning,the device of emulsion electrospinning iseasier and more convinient.W/O emulision is used to make biological active substance ordurg loaded nanofiber.However,there is seldom study on the process of emulsion.In thisthesis,we chose polylatic acid (PLA) as oil phase,chose polyvinyl pyrrolidone (PVP) andalginate sodium (SA) as water phase to study the influence of solution properties and voltageon the process of emulison electrospinning with single needle electrospinning device.For PVP/PLA emulsion, aqueous PVP solution can improve the spinnability of PLAsolution with low concentration.The fiber diameter increase with the increase of voltagewhich is not common.Because surfactant molecules in the surface of PVP micelles impel PLAchains to migrate towards the micelles which enforce the entanglement of PLAchains.Increasing voltage, volume fraction of PVP,diameter of micelles led to the aggravationof entanglement and resulted in bigger fiber diameter.Because of the low conductivity ofPVP,the voltage had little influence on the behavior of PVP micelles.Water treatment,TG andhydrophilic test indicated that most of PVP was on the surface of PVP/PLA nanofiber,andhigh concentration PVP solution can make seperated PVP fiber from the surface of PLA fiber.Because SA is polyelectrolyte with good conductivity,SA micelles were induceddeformed by electric field. Na+with positive charge arranged in the inner of jet and alginatewith negetive charge migrated towards the interface of jet and air.EDS test found few Na+inthe surface of fiber and IR test indicated the alginate mainly distributed in the surface offiber,which confirm the induced-deformation mechanism.Overall,the process of W/O emulision electrospinning is complicated.The behaivor ofmost polymer dispersion is influenced by solution properties.For some dispersion with goodconductivity,besides solution properties, electric field also has great influence on the process.