An acoustic platform for facile, size-targeted polymeric nanoparticle synthesis

A nanoparticle synthesis platform exploiting acoustic irradiation was developed and found to be capable of reproducibly synthesising particles of different sizes. In this platform, acoustic emulsification is used to generate dispersed droplets that are subsequently converted into solid nanoparticles upon solvent removal. This work shows that acoustic emulsification can be used to transform nanoparticle synthesis from a qualitative, empirically optimized technique into a predictive platform for size control by linking cavitation-driven droplet formation to simple, experimentally validated design rules. This size control was readily achieved through the variation of two parameters: acoustic frequency and polymer concentration. Changes in frequency produced substantial shifts in particle size, with lower frequencies (132 kHz) generating larger cavitation bubbles that collapse more violently and produce smaller dispersed droplets, while adjustments in polymer concentration allowed for finer tuning of particle size upon solvent removal. Across the investigated combinations of frequency and polymer concentration, particle sizes in the range of 51-177 nm were obtained. Under the investigated conditions, the estimated droplet size for a given frequency remained independent of polymer concentration, enabling the application of a simple mass balance to predict the polymer concentration required to obtain the desired particle size.