Engineering Polymer Microparticles by Droplet Microfluidics

Capillary-based flow-focusing and co-flow microsystems were developed to produce sphere-like polymer microparticles of adjustable sizes in the range of 50 to 600 mu m with a narrow size distribution (CV < 5%) and different morphologies (core-shell, janus, and capsules). Rod-like particles whose length was conveniently adjusted between 400 mu m and few millimeters were also produced using the same microsystems. Influence of operating conditions (flow rate of the different fluid, microsystem characteristic dimensions, and design) as well as material parameters (viscosity of the different fluids and surface tension) was investigated. Empirical relationships were thus derived from experimental data to predict the microparticle's overall size, shell thickness, or rods length. Besides morphology, microparticles with various compositions were synthesized and their potential applications highlighted: drug-loaded microparticles for new drug delivery strategies, composed inorganic-organic multiscale microparticles for sensorics, and liquid crystalline elastomer microparticles showing an anisotropic reversible shape change upon temperature for thermal actuators or artificial muscles.