Thermoformed fluoropolymer tubing for in-line mixing

We present a thermoforming method to make in-line micromixer in commercial fluoropolymer tubing. The technique is low-cost and easy to implement in the laboratory. Tested by dye tracing experiments, the tubular micromixers with surface screw patterns demonstrate excellent performance as characterized by the Villermaux–Dushman reaction and computational fluid dynamics (CFD) simulations. Results show that the formed static mixer performs better than coiled and straight tubes for the low Reynolds number (Re < 100) regime encountered in many laboratory flow chemistry experiments. The observations correlate well with residence time distribution (RTD) experiments revealing reduced dispersion. The improved performance of the screw-tube mixers is attributed to the forced rotating flow around the central axis. The new static mixer structures are employed in the synthesis of gold nanoparticles with high yield and narrower size distribution particles compared to results with coiled tubes.