Materials selection and manufacturing of thermoplastic elastomer microfluidics

In this paper we outline some of the manufacturing advantages and challenges of working with thermoplastic elastomers as an alternative to traditional polydimethysiloxane (PDMS) for flexible and reversibly bonded microfluidic systems. Unlike PDMS, thermoplastic elastomers can be processed with many industrial polymer manufacturing technologies such as extrusion, injection molding, hot embossing and others, potentially permitting much more scalable production and cheaper costs per part. Unlike a more rigid thermoplastic, these thermoplastic elastomers are typically much easier to bond, either reversibly or permanently due to their inherent compliance and subsequent low pressures necessary to seal channels and reservoirs. Unlike PDMS however, where one material (Sylgard 184) dominates the literature, there have not been many in depth investigations into thermoplastic elastomers and their relative performance and applicability to microfabrication. We show a comparison between several categories of thermoplastic elastomer to demonstrate what issues may be encountered and to demonstrate that even for labs with minimal equipment, academic prototyping with these materials is not necessarily any more challenging than PDMS.