Solvent-resistant and fully recyclable perfluoropolyether-based elastomer for microfluidic chip fabrication

Polydimethylsiloxane (PDMS) is a popular choice for microfluidic chip fabrication, while it still meets several significant challenges, including poor solvent compatibility, non-reprocessability, and non-recyclability. Innovations of new elastomers that can get rid of these drawbacks are capable to push forward the application of microfluidics in organic synthesis and avoid potential environmental threats from waste chips. Here, we report a kind of solvent-resistant perfluoropolyether (PFPE)-based thermoset elastomer that can be reprocessed like thermoplastics and degraded back to its raw material. The solvent-resistant elastomer is synthesized by crosslinking PFPE-diol into a dynamic covalent network. As PFPE chain is repellent to most solvents, this PFPE-based elastomer exhibits much lower swelling ratios in comparison with PDMS. Dye diffusion experiments on microfluidic chips convince the success in preventing swelling-induced dye leakage or diffusion. To present the thermoplasticity and reprocessability, one specific spiral microfluidic chip is cut into small pieces and reshaped into another chip for allowing laminar flow between two types of solutions. Besides, the PFPE-based elastomer is chemically degradable and over 90% PFPE-diol is recycled. This solvent-resistant and fully recyclable elastomer provides a new material choice for microfluidics and is bound to play an important role in microfluidic researches with respect to organic chemistry.