Binary-Cooperative Patterned-Crisscrossing Membranes with Gas Separation

Polymer membranes remain indispensable in gas separation technologies due to their superior processability and low cost. Cross-linking serves as an effective approach to improve separation performance. However, under high operation pressure, highly cross-linked polymers only exhibit slightly enhanced selectivity but suffer from low permeability and brittleness, whereas their lowly cross-linked counterparts offer high permeation and flexibility at the expense of selectivity. Hence, it remains difficult to maintain high gas permeation and selectivity under high pressure. To transcend this limitation, we designed a nature-inspired patterned-crisscrossing polymer (PCCP) membrane featuring a patterned architecture of alternating high- and low-cross-linking zones via a zone-thermal-cross-linking strategy. In this configuration, the PCCP structure produces a cooperative stress transfer and swelling inhibition effect that effectively maintains a stable structure and a high permselectivity simultaneously. The optimal PCCP membrane demonstrated a stable CO₂ permeance of 4973 GPU and a CO₂/CH₄ selectivity of 42 at 3.0 MPa─representing a 4-fold enhancement over conventional single-cross-linking membranes and positioning it among the top-performing systems reported to date. This patterned design concept suggests a new design of next-generation molecularly selective membranes toward industrial gas separation under harsh conditions.