Biodegradable Polylactide-co-glycolide (PLGA) Thin Films Prepared by Electrospray and Pressurized Spray Deposition

PLGA thin films were prepared onto implantable devices by the electrospray and pressurized spray method. Thin films with structural gradients were obtained by controlling four parameters consisting of solution concentration, applied voltage, air pressure , and deposition time. The surface morphologies of the deposited films were observed using scanning electron microscopy （SEM）. The image analysis revealed the control factors on the preparation of PLGA thin films. The beaded structure is ensily formed with a decrease in polymer concentration while the fibrous structure is easily formed with an increuse in polymer concentration. With the increase in applied voltage, the surface morphologies changed continnously from a small amount of fibrous shape to a large fibrous one： a small amount of.fibrous shape at 10 kV, more fibers with non-uniform diameter at 20 kV, and most fibers with uniform diameter at 30 kV. Low air pressure（0.1 MPa ） corresponded to round particles while high air pressure （0.3 MPa ） corresponded to fiat particles. The change in thickness from 5.34 to 10.1μm was a result of deposition time increasing from 5 to 10 s. From our above work, films of the bead or fiber structures can be obtained by changing electrical parameters to impropvc tbe biocompntibility of the film.