Flow synthesis of poly(acrylamide-co-acrylic acid) microspheres in a microreactor: Experimental and CFD studies

Abstract

A microfluidic platform to synthesize monodispersed and spherical hydrogel beads (microspheres) of poly(acrylamide-co-acrylic acid) (p(AM-co-AA)) is reported. An aqueous phase consisting of monomer, cross-linker, functional moiety and initiator, all dissolved in water, is dispersed as uniform drops of desired size into a carrier phase (dodecane) at an opposed T-junction. The chemical and physical properties of the microspheres are systematically studied. Effects of operating parameters like velocity and O/A (oil to aqueous phase flow ratio) ratio on the average size, polydispersity and shape of microspheres are investigated. Microspheres within a size range of 960 to 502 microns can be synthesized. A comparison of two different mixing techniques namely in-situ and ex-situ mixing is also presented. A two dimensional computational fluid dynamic (2 D CFD) model is also developed to quantify and validate drop formation phenomena at the T junction at extreme O/A ratios. Detailed numerical insights on the velocity and pressure field at the junction have been provided.

Graphical Abstract

Keywords:

• CFD
• microfluidics
• microspheres
• T-junction
• polymerization

Additional information

Funding

No funding was received for the work reported in this communication