Electrosprayed particles were collected on a microscope slide, cut, and mounted on aluminium SEM stubs using a double-sided carbon sticker (TAAB Laboratories, UK). These stubs were subsequently gold-coated to make the samples conductive for SEM (Thermo Scientific Phenom Pro G6 Desktop SEM). To verify the technique's reproducibility, the NPs were electrosprayed three times. ImageJ (NIH, USA) determined the particle size distribution by analysing three images with their “Analyse particle” functions and the size was determined from the measured NPs area. The dataset above shows the calculated diameter of the particles from the measured area.