Microfluidic-Based Synthesis of Acrylamide/Sodium Acrylate Copolymer Hydrogel for Enhanced Properties

Abstract

Hydrogels are commonly used in drug delivery1–3, water treatment for heavy-metal removal4, tissue engineering5, and hygienic products, and as a plugging agent for enhanced oil recovery6. In recent years, a number of chemical reactions and polymerization have been developed in microfluidic devices. The products in microfluidics have a better control over size, size distribution, morphology, and chemical composition. In this work, the poly (acrylamide-co-sodium acrylate) hydrogel micro-particles with enhanced properties were synthesized in the microfluidic device. We developed a simple experimental method (inverted-chip method) to synthesize the hydrogel micro-particles in the microfluidic device. The product micro-particles have a narrow size distribution; and their morphology is similar. The swelling property was controlled by varying the feed monomer composition and crosslinker concentration. As a result, the hydrogel micro-particles swell faster and larger than the bulk polymer. The volume swelling ratio depends on the crosslinker concentration and the ionic content in the polymer. A lower crosslinker concentration absorbs and retains more water than a higher crosslinker concentration. The high-ionic-content polymer micro-particles have a higher swelling ratio than do those with lower ionic content.