pps proceeding - Abstract Preview
pps proceeding
Symposium: S01 - Advanced Processing and additive Manufacturing
Keynote Presentation
 
 

Continuous Manufacturing Of Gel And Aerogel Microparticles and Microrods

Jana Sadhan C (1)*

(1) University of Akron - OH - USA

There is a need for large quantities of extremely porous (>90% porosity) polymeric gel and aerogel microparticles and microrods with diameter in the range of 200-1000 m to serve as catalyst supports, drug carriers, carrier of phase change materials, and as agents for breaking oil/water emulsions. However, current technologies based on capillary breakup cannot be easily retrofitted to obtain precise control of particle diameter, to induce core-shell morphologies, or to convert the polymeric domains into microrods of length to diameter ratio of approximately 50. In this context, our work focuses on adaptation of microfluidic flows and identifies operational regimes for continuous manufacturing of soft and hard gel particles from polyimide which are later supercritically dried to yield corresponding aerogel counterparts. The first part of the talk will focus on fabrication of polyimide aerogel microparticles of diameter 200-1000 µm from a surfactant-free, two-phase, silicone oil/dimethylformamide (DMF) oil-in-oil (O/O) system using a simple microfluidic device. The polyimide sol prepared in DMF is turned into droplets suspended in silicone oil in the microfluidic device. The droplets are guided to a heated silicone oil bath to accelerate sol-gel transition and imidization reactions, thereby yielding spherical, discrete gel microparticles that do not undergo coalescence. The discrete gel microparticles are isolated and supercritically dried to obtain aerogel microparticles. The microparticle size distribution shows dependence on dispersed and continuous phase flowrates in the microfluidic channels. The microparticle surface morphology shows dependence on silicone oil bath temperature. In the second part, a novel microfluidic process is discussed for continuous manufacturing of core-shell microparticles with mesoporous shell materials and microrods of aspect ratio 50-100 by manipulating the interfacial and viscous forces and the sol-gel transition kinetics.