In this study, monodisperse poly(acrylamide-co-sodium acrylate) hydrogel microparticles with a controlled water absorbance capacity were synthesized in a droplet microfluidic device that can be used for enhanced oil recovery applications. The experimental method and the microfluidic device were optimized to produce well-spaced monodisperse monomer droplets that were then polymerized by UV initiation in an oil reservoir. The monomer composition (acrylamide-to-sodium acrylate weight ratio) and the cross-linker concentration were tailored to increase the water absorbance capacity. The copolymer composition was evaluated and confirmed by FTIR spectroscopy measurements. The water absorbance capacity determined by swelling experiments agreed very well with that predicted by Flory-Huggins swelling theory, which relates swelling to the ionic content and the cross-linker concentration.