Investigation of the Influence Mechanism of Droplet Diameter in Electrospray Atomization and Breakup Based on Response Surface Methodology

ABSTRACT Electrostatic spray technology enables the formation of micro‐/nano‐scale droplets via high‐voltage‐induced liquid breakup, and is widely applied in drug microsphere encapsulation and functional film fabrication. However, the droplet size is influenced by multiple interacting parameters, and its control mechanism remains insufficiently understood, limiting industrial precision. This study combines COMSOL finite element simulation with response surface methodology (RSM) to systematically investigate the droplet breakup mechanism and key parameter effects. Simulation reveals electric field strength and velocity distributions, highlighting electro–fluid coupling during atomization. Based on preliminary single‐factor tests, a Box–Behnken design was used to assess the effects of voltage, spray distance, and flow rate on droplet size. A predictive model was developed and validated through residual analysis and experiments. Under a 5% polyvinylidene fluoride (PVDF) solution, the optimized parameters—17 cm spray distance, 15 kV voltage, and 0.4 mL/h flow rate—yielded a predicted droplet diameter of 1.3931 µm, closely matching the measured value of 1.3887 ± 0.1787 µm (error < 1%). This work provides both theoretical insight and a practical approach for precise droplet size control in electrostatic spraying, supporting its application in advanced material processing and drug delivery systems.