Fabrication of poly(lactic acid) nano‐ and microparticles using a nanomixer via nanoprecipitation or emulsion diffusion

In order to investigate the influence of mixing flow condition on particle generation, poly(lactic acid) (PLA) particles were fabricated at different mixing velocities (10–50 m s −1 ) using a nanomixer through either the nanoprecipitation or the emulsion diffusion method. With a nanomixer (Couette–Taylor mixing geometry modified with cavitations), particles became smaller as the mixing velocity increased as long as the temperature was kept below the glass transition temperature ( T g ) of PLA. Even in the emulsion diffusion method, it led to the formation of PLA nanoparticles in a short emulsification time (∼1 min) and the mean diameter was less than 100 nm with deviation less than 10% (100 nm ± 10%). However, at high mixing velocity, the particle size was rapidly increased which was enhanced as mixing time increased. Dissipation rapidly increased the temperature inside the mixer above T g of PLA, which caused smaller particles to agglomerate to form larger micron‐sized particles. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46199.