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 degrees C, Young's modulus of 770 MPa and hydrophilic surface having a water contact angle of 54 degrees. Micromolding of 33 mu m thick HBP microstructures has been demonstrated. We achieved 14.5 mu m wide vertical walls, 14.7 mu m wide fluidic channels, 24.1 mu m-wide square pillars and 53.4 mu m 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.