Polymer Particles with Various Shapes and Morphologies Produced in Continuous Microfluidic Reactors

Abstract

We report a novel approach to continuous and scalable production of core-shell droplets and polymer capsules in microfluidic devices. The described method is also useful in the synthesis of polymer particles with nonspherical shapes. We used capillary instability-driven break-up of a liquid jet formed by two immiscible fluids. Precise control of emulsification of each liquid allowed for the production of highly monodisperse core-shell droplets with a predetermined diameter of cores and thickness of shells. We also achieved control over the number of cores per droplet and the location of cores in the droplet. We carried out fast throughput photopolymerization of the monomeric shells and obtained polymer particles with various shapes and morphologies, including spheres, truncated spheres and, hemispheres, and single and multicore capsules.

Porous polymer particles—A comprehensive guide to synthesis, characterization, functionalization and applications

“…It is the elaborate chip design that allowed researchers not only to miniaturize microchannel emulsification reactors and prepare narrowly monodisperse spherical beads but also to achieve unprecedented control over structure and shape of particles. This unique capability of control resulted in the realization of perfectly controlled multiple emulsions [136][137][138][139][140][141][142][143][144][145], Janus particles [146][147][148][149][150][151][152][153][154][155][156], regular nonspherical shapes [157][158][159][160][161][162][163][164][165][166] and even gas bubbles [167][168][169][170][171], almost all of which were impossible to achieve before.…”

Emulsification in a microfluidic flow-focusing device: effect of the viscosities of the liquids

“…Recently, several research groups have reported synthesis of polymer particles in microfluidic reactors (Cohen et al 2001;Dendukuri et al 2005;Jeong et al 2005;Lewis et al 2005;Loscertales et al 2002;Nie et al 2005Nie et al , 2006Nisisako et al 2004;Seo et al 2005aSeo et al , 2005bTakeuchi et al 2005;Utada et al 2005;Xu et al 2005;Zhang et al 2006). The syntheses included a two-step process: (1) microfluidic emulsification of monomer or polymeric fluids, and (2) subsequent in-situ (on chip) solidification of the droplets by means of polymerization, gelation, or solvent evaporation.…”

“…The syntheses included a two-step process: (1) microfluidic emulsification of monomer or polymeric fluids, and (2) subsequent in-situ (on chip) solidification of the droplets by means of polymerization, gelation, or solvent evaporation. Microfluidic methods allowed for the production of particles with diameters from several micrometers to hundreds of micrometers, polydispersities below 5%, and shapes and morphologies that were not achievable in the conventional synthesis of colloids (Nisisako et al 2004;Xu et al 2005;Nie et al 2005Nie et al , 2006Dendukuri et al 2005). Such particles have a broad range of potential applications including their use as ion exchange resins, spacers, calibration standards, and carriers for drugs, nutrition, pharmaceutical, and cosmetics agents.…”

Preparation of hemispherical polystyrene particles utilizing the solvent evaporation method in aqueous dispersed systems

“…In general, polymer particles synthesized by heterogeneous polymerizations under thermodynamic control have a spherical shape because of interfacial free energy minimization. However, nonspherical polymer particles have been synthesized under kinetic control utilizing various seeded polymerization methods, [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] microfluidic techniques, [25][26][27][28] deformation of spherical polymer particles by external force, [29][30][31] the stepwise heterocoagulation method 32,33 and the self-organized precipitation method. 34 In a previous work, we proposed a novel approach for the preparation of micrometer-sized, monodisperse, nonspherical (i.e., dimpled and hemispherical) polystyrene (PS) particles by successive heating and cooling of spherical PS particles dispersed in a methanol/ water medium in the presence of droplets of decane.…”