Controllable Monodisperse Amphiphilic Janus Microparticles

Abstract

A facile microfluidic strategy has been successfully developed in this paper for the controllable fabrication of monodisperse amphiphilic Janus microparticles. The fabrication of such amphiphilic Janus microparticles is simply achieved by online UV curing of monodisperse Janus droplet templates that are prepared from microfluidics together with initial fast phase separation induced by co-solvent diffusion and sequential dewetting triggered by interfacial energy. Benefitting from the superiorities of droplet microfluidics, the morphologies of Janus microparticles can be flexibly and precisely controlled by adjusting the flowrates of fluids and the compositions of dispersed phase. Meanwhile, the functionalization of Janus microparticles can be easily realized by introducing certain elements into the dispersed phase to rationally design the bulbs with diverse advanced functions. We also demonstrate the universality of the proposed strategy through the fabrication of monodisperse Janus microparticles with one bulb consisting of hydrophobic poly(ethoxylated trimethylolpropane triacrylate) and another bulb consisting of a hydrophilic hydrogel such as poly(N-isopropyl acrylamide), poly(N-vinylcaprolactam), or polyacrylamide. The thermoresponsive hydrophilic/hydrophobic phase transition property of the poly(N-isopropyl acrylamide) bulb enables the Janus microparticles to be used as functional colloidal surfactants for adjusting the stability/instability of oil–water interface. Our strategy provides a versatile and efficient way to fabricate monodisperse amphiphilic Janus microparticles with controlled structures and diverse functions, which show great application potentials in plenty of fields.