Investigation of electrohydrodynamic atomization (electrospraying) parameters' effect on formation of poly(lactic acid) nanoparticles

The aim of this study was to develop nanoparticles via electrohydrodynamic atomization (electrospraying) method. These nanoparticles have potential applications such as drug delivery and manipulating surface functionality. Electrosprayed nanoparticles were produced from poly(lactic acid) (PLA). Solution and process parameters were investigated for optimization of the electrospraying process. Different PLA concentrations, solvent types and solvent ratios were investigated as part of the study. The characterization of the electrosprayed solutions was carried out via viscosity, conductivity and surface tension measurements. Also, the effect of process parameters (flow rate, needle to collector distance, electrical field, application time and needle dimension) on particle morphology and dimension was investigated. After the formation of PLA nanoparticles, morphological and dimensional characteristics were analyzed through SEM images and nanosizer measurements. According to some of our findings, particle size increases with higher polymer concentrations and flow rates. Also, increase in electrostatic field and distance result in smaller particle size because of increase in coulombic forces. But a further increase in coulombic forces triggers increase in size of particles and fibril formation with a bimodal distribution. The smallest size and the narrowest distribution were obtained for the smallest inner needle diameter. Deposition time does not have a significant influence on the produced particle sizes and their distributions; it only affects the production amount. As a result of this study, desired monodisperse PLA nanoparticles with comparatively smaller size were successfully achieved. Also, the detailed investigation of electrospraying parameters can be useful for future studies.