Continuous fabrication of core-shell aerogel microparticles using microfluidic flows

摘要

This work focuses on fabrication of core-shell polyimide aerogel microparticles with and without a surfactant via oil-in-oil-in-oil (O/O/O) emulsion system aided by a simple microfluidic device. A double emulsion is formed through sequential, step-wise emulsification of co-flowing core and shell organic liquid streams in a simple microfluidic setup. The polyimide sol, introduced as the shell liquid, undergoes accelerated polymerization in a heated silicone oil bath to yield a porous polyimide shell around silicone oil core that eliminates the possibility of droplet coalescence or rupture. The core-shell gel microparticles are then isolated and supercritically dried to obtain core-shell aerogel microparticles. The diameter and shell thickness of hollow microparticles are studied as function of liquid flowrates in the microfluidic device and the viscosity of the shell liquid. (C) 2019 Elsevier Inc. All rights reserved.