Superior dry bonding of off-stoichiometry thiol-ene-epoxy (OSTE(+)) polymers for heterogeneous material labs-on-chip

Saharil, Farizah [KTH Royal Institute of Technology, Sweden] El Fissi, Lamia [UCL] Liu, Yitong [KTH Royal Institute of Technology, Sweden] Calborg, Fredrik [KTH Royal Institute of Technology, Sweden] Vandormael, Denis [SIRRIS, Liège] Francis, Laurent [UCL] van der Wijngaart, Wouter [KTH Royal Institute Of Technology, Sweden] Haraldsson, Tommy [KTH Royal Institute Of Technology, Sweden] et al.[show all]

We demonstrate biocompatible bonding to a multitude of LoC substrates using OSTE(+), a novel polymer formulation with a unique dual cure system developed specifically for microfluidic applications. OSTE(+) allows for soft lithography microstructuring, strong biocompatible dry bonding to almost any substrate during LoC manufacturing, while simultaneously mimicking the mechanical properties found in thermoplastic polymers, hence allowing for true prototyping of commercial LoCs. In this work, we describe the simple micropatterning process, curing mechanisms and show leak-free dry bonding to nine different substrate materials. Uniquely, strong bonding is achieved to COC, the thermoplastic of choice for microfluidics, which opens up the possibility of hybrid thermoplastic/OSTE(+) LoCs. In this work, we demonstrate bonding to nine different untreated substrates at 37°C and room temperature to demonstrate good bonding properties even at lower temperature. We also show the high resilience of the epoxy bond by immersing an aluminum substrate with a bonded OSTE(+) layer into boiling water while simultaneously subjecting the assembly to pressurized air.