Additively Manufactured Robust Microfluidics via Silver Clay Extrusion.

We report novel, low-cost, high-temperature compatible, high-pressure compatible, and chemically resistant additively manufactured microfluidics. The devices were monolithically fabricated by extruding silver clay with a fused filament fabrication 3D printer frame fitted with a syringe extruder, followed by annealing at 885 °C in air. Analysis of the printable feedstock shows that the green material is an alloy composed of silver and copper microparticles blended with an organic binder matrix, while analysis of printed and annealed samples shows that the material is completely free of binder and compatible with at least 800 °C operation. Characterization of the thermal, electrical, and mechanical properties of printed and annealed structures yields values close to those of bulk sterling silver, except for a significantly smaller Young’s modulus. Metrology of test structures evidences linearity between printed dimensions and computer-aided design values. Layers as thin as $150~\mu \text{m}$ and working, watertight closed channels as narrow as $200~\mu \text{m}$ were consistently resolved. A proof-of-concept microfluidic that catalytically decomposes hydrogen peroxide was designed, fabricated, and characterized; the experimental performance of the catalytic microreactor is in agreement with reduced-order modeling. [2019-0267] [ABSTRACT FROM AUTHOR]