Hot embossing of microfluidic channel structures in cyclic olefin copolymers

The dynamic mechanical behaviour of a series of cyclic olefin copolymers (COCs) with varying norbornene content has been examined in the vicinity of the glass transition temperature, Tg. The temperature of the transition has been shown to increase linearly with increase in norbornene content. Measurements of both the elastic storage modulus, E', and loss modulus, E?, have decreased exponentially with rise in temperature above Tg . A levelling-off in E? occurred at >20 °C above Tg for all copolymers. The results of Dynamic Mechanical Thermal Analysis (DMTA) have been used in the identification of optimum conditions for hot embossing. At >20 °C above Tg in a region of viscous liquid flow, the hot embossing of COC has resulted in a full replication of channel depth without cracking or distortion.