A fast low-temperature micromolding process for hydrophilic microfluidic devices using UV-curable acrylated hyperbranched polymers

Abstract

A novel UV-curable low-stress hyperbranched polymer (HBP) micromolding process is presented for the fast and low-temperature fabrication of hydrophilic microfluidic devices. Process, material and surface properties of the acrylated polyether HBP are also characterized and compared to those of polydimethylsiloxane (PDMS) and cyclic olefin copolymers (COC). The HBP dispensed on a PDMS master was cured at room temperature using a 3 min UV exposure at the intensity of 22.2 mW cm−2. Thermal, mechanical and surface properties of the micromolded HBP structures have been characterized and resulted in a glass transition temperature of 55 °C, Young's modulus of 770 MPa and hydrophilic surface having a water contact angle of 54°. Micromolding of 33 µm thick HBP microstructures has been demonstrated. We achieved 14.5 µm wide vertical walls, 14.7 µm wide fluidic channels, 24.1 µm wide square pillars and 53.4 µm wide square holes. A microfluidic network device, composed of microfluidic channels and reservoirs, was fabricated and its microfluidic performance has been verified by a fluidic test.