Study On The Process Of Emulsion Electrospinning

Compared to co-axial electrospinning, emulsion electrospinning process is bettercontrollable, and can be used more widely. Emulsion electrospinning has very specialsignificance in making nanofibers with active substance, special drugs and functions. Thereare many literatures about emulsion electrospinning in biomedical, but the research aboutmechanismof it, especialthe emulsionstatus underelectrical fieldwas verylimited.In this thesis, three kinds of emulsion were made, alginate sodium (SA)-Polylactic acid(PLA) W/O emulsion, Dicyclopentadiene (DCPD)-PEO O/W emulsion and PEO emulsionincluding NP nanoparticles. The percentage of dispersed phase in emulsion, the kind ofsurfactant and voltage used in electrospinning had great effect on process of electrospinningandthestructureof fibers.Firstly, process of SA-PLA (W/O) emulsion elctrospinning was investaged. Ultrafinefibers can be obtained by emulsion electrospinning. The minimum voltage used inelectrospinning was increased with increasing the percentage of alginate sodium solution inemulsion. Based on FTIR studies of emulsion electrospinning fiber mats, the peak at1755cm-1is associated with SA which indicated theexisting of SA in fibers. The TG of fibermat demonstrated that the thermal stability of fibermats became worse with the increasing ofSA. From the (confocal laser scanning microscope) CLSM images, SA was found all aroundthefibers,which indicatedthat some SA weredispersedon the surfaceof fiber.However, as for DCPD/PEO emulsion whose dispersed phase was small molecule withlow boiling point, the kind of surfactant had significant effect on the properties of O/Wemulsion and then the process of electrospinning.The conductivity of emulsion stabilized byionicsurfactant (SDS) was much higher than that stabilized by nonionic surfactant. Besides,as for emulsion stabilized by SDS, demulsification would take place under external electricfield, when the percentage of DCPD increased to50%, almost all dispersed phase DCPD wasreleased from micelle under electric field, finally DCPD was volatilized duringelectrospinning.Finally,process of electrospinning PEO emulsion whichincluded solid nanoparticles (NP)was investaged, amount of solid nanoparticles and surfactants which used stabilizednanoparticles had significant effect on the properties of emulsion and morphology of finalfibers. FTIR of fiber mats indicated exist of interaction between PEO and solidnanoparticles.With increasingamount of solidnanoparticles, the interaction between PEOandsolid nanoparticles strengthed, the viscosity increased greatly. In emulsion electrospinning, when NP: PEO is0.3:1,the fiber was similar to “sausage”, this interestingphenomenon wasviscous relied and more “sausage” fibers were found when used higher voltage. WhenNP:PEO≥0.6:1, the “sausage” fibers disappeared because of higher viscosity of emulsion,nanoparticleswas encapsuledinthe coreof fiberandPEOexisted in theshell.