Development of a Method for Fabrication of Microfluidic Rheometers from Epoxy Resin

The work is devoted to the development and fabrication of durable, transparent, and accessible microfluidic chips made of epoxy resin for studying the rheological and physicochemical properties of oilfield fluids. The chips were fabricated using a casting method (pour-into-mold) from an epoxy compound (KER-215 resin and Sintamin hardener) using polydimethylsiloxane (PDMS) master molds. This work resulted in prototypes of microfluidic viscometers and rheometers designed to measure the viscoplastic and viscoelastic properties of fluids. Chips with various topologies were fabricated, including a hyperbolic constriction, a fan-shaped channel, and curved channels for studying secondary flows (Dean vortices). The resulting topologies enable not only standard measurements of the pressure drop versus flow rate, but also the determination of rheological properties based on the shape of streamlines and the behavior of vortex structures. The functionality of the chips was confirmed by experiments with non-Newtonian fluids, yielding pressure drop versus flow rate dependences suitable for determining viscosity and other rheological parameters. The developed epoxy microfluidic chips offer a promising and cost-effective platform for rapid analysis of the rheological properties of oilfield fluids, which is particularly relevant for selecting the optimal composition of displacement fluids in oil production.