(163b) Plasma-Radiation Enhanced Nanofiber-Thermoplastic Composites

Electrospun nanofibers are finding a wide variety of applications such as in tissue scaffolds, novel polymer architectures and nanocomposite reinforcement. The main advantage of such ultrafine fiber systems is their high specific surface area which gives rise to improved properties at nanoscale confinement. We are interested in synthesizing thermoplastic nanofibers enmeshed within another polymer phase in order to have polymer-polymer nanocomposite membranes which are eventually to be applied in membrane systems displaying improved and controlled permeation selectivity. Our approach involves the surface treatment of electrospun polysulfone (PSU) nanofibers by a dielectric-barrier-discharge (DBD) plasma followed by surface grafting reactions in order to affix hydrophilic polymer chains around a hydrophobic PSU core. The effect of post irradiation parameters such as treatment times, temperatures and silanization has been studied in order to determine optimum grafting reaction conditions. We have been able to show the controlled synthesis of sub-micron fibers with greatly improved wettability and successful grafting chemistry as determined by contact angle and IR spectroscopic analyses respectively. In addition, plasma treated nanofibers encapsulated within a polyethylene based ionomer matrix shows a significantly improved fiber-matrix interface as opposed to non-plasma treated composite systems which displays poor wetting between the phases.