Multifunctional Microfluidic Devices from Tailored Photopolymer Formulations

摘要

Here, we demonstrate the additive manufacturing of two key microvalve designs, namely Nordin’sand Quake’s microvalves, based on a formulation consisting of tri(propylene glycol) diacrylate(TPGDA) as a base material, diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO) as aphotoinitiator and Sudan1 as the UV-absorber via micro-stereolithography (μSL). Mechanicalmeasurements of test prints show an average Young’s modulus of 15.7 MPa, which is eight timeslower compared to several previous studies on 3D-printed microvalves and micropumps based onpoly(ethylene glycol diacrylate) 258 (PEGDA-258). We use a high-resolution Cerafab7500 printer(Lithoz GmbH, Vienna) with a minimal lateral resolution of 10.3 μm to print membrane valves withvoxel dimensions down to 60 μm. Particularly, we study the effect of different comonomers added tothe photopolymer formulation – neopentyl glycol propoxylate (1 PO/OH) diacrylate (NPGPDA), 1,6-hexanediol diacrylate (HDDA) and 2-phenoxyethyl acrylate (POEA) – on the layer thickness, which isidentified to be a crucial parameter. 3D-printed valves are tested regarding maximum operatingpressure withstanding pressures of up to 5 bar. We show that TPGDA-based resins combine highflexibility, mechanical stability, and sufficient resolution for the future design of flow control units inmicrofluidics.