Fig. 5
High-throughput production of polycaprolactone microparticles. a Optical image of droplet generators producing monodisperse emulsion templates. The dispersed phase Φd is 133 g L−1 of polycaprolactone (PCL) in dichloromethane (DCM), and continuous phase Φc is 2 wt% of polyvinyl alcohol (PVA) in water. b Emulsion of 8.76 L could be generated in 75 min. c. Evaporation of dichloromethane from emulsion templates as a function of time. Scale bar: 10 µm. d An SEM micrograph of PCL microparticles, produced at 277 g h−1. Scale bar: 20 µm. e Top and side view of a single PCL microparticle. Scale bar: 10 µm. f–i SEM micrographs of PCL microparticles generated with particle diameter dp using a template diameter dT. Scale bar: 10 µm. Using 133 g L−1 PCL, we generated particles: f dP = 11.2 µm (CV = 4.4%), dT = 23.2 µm (CV = 2.5%) at 277 g h−1 and g dP = 16.1 µm (CV = 4.4%), dT = 35.9 µm (CV = 1.4%) at 109 g h−1. Using 53.2 g L−1 PCL, we generated particles: h dP = 8.4 µm (CV = 4.0%), dT = 24.5 µm (CV = 2.4%) at 76.8 g h−1 and (i) dP = 15.2 µm (CV = 3.6%), dT = 42.7 µm (CV = 2.0%) at 38.5 g h−1. Histograms of template diameters and particle diameters produced using 133 g L−1 PCL (j) and 53.2 g L−1 PCL (k). l The measured particle diameters dT agreed well (R2 = 0.99) with the particle diameter predicted based on the template diameter dT, ρE is the wt/vol concentration of PCL in our emulsions, and ρPCL = 1.143 gmL−1 is the density of solid PCL. The gray line represents ideal agreement between the particle size dP and the prediction
