Poly(4-methyl-1-pentene) (PMP) membranes prepared by mixed solvent phase separation with superior omniphobicity for high-performance extracorporeal membrane oxygenation (ECMO)

Abstract

Membrane wetting poses a critical barrier to the long-term performance and safety of extracorporeal membrane oxygenation (ECMO) systems. To address this challenge, here we report the fabrication of highly hydrophobic and porous poly(4-methyl-1-pentene) (PMP) membranes using a mixed solvent phase separation (MSPS) method. This strategy enables a streamlined, one-step fabrication process at moderate temperatures (≤ 65°C), effectively overcoming the processing limitations of traditional PMP membranes. The resulting membrane exhibits a hierarchical porous architecture, featuring a high density of micrometer-scale pores on the surface and a sponge-like porous network within the bulk. The distinctive surface morphology imparts exceptional omniphobicity, with a water contact angle of 156.6° ± 0.9. The interconnected channels bridging the surface and the bulk were found to be around 21 nm, which generates a robust liquid entry pressure exceeding 10 bars, ensuring leak-free operation for more than 7 days. Furthermore, the high-density surface pores facilitate an outstanding oxygen transfer rate of 156 ml min⁻¹ m⁻² in a mock ECMO circuit, marking one of the highest reported values for PMP-based membranes.